Add ORDER BY to make the test deterministic.

Add FLUSH TABLES to avoid crash recovery warnings about the table
mysql.plugin. This tends to occur on Valgrind, where the server
shutdown could presumably time out, resulting in a forced kill.

dict_table_rename_in_cache(), dict_table_get_highest_foreign_id():
Reserve sufficient space for the fkid[] buffer, and ensure that the
fkid[] will be NUL-terminated.

The fkid[] must accommodate both the database name (which is already
encoded in my_charset_filename) and the constraint name
(which must be converted to my_charset_filename) so that we can check
if it is in the format databasename/tablename_ibfk_1 (all encoded in
my_charset_filename).

Modern software (including text editors, static analysis software,
and web-based code review interfaces) often requires source code files
to be interpretable via a consistent character encoding, with UTF-8 or
ASCII (a strict subset of UTF-8) as the default. Several of the MariaDB
source files contain bytes that are not valid in either the UTF-8 or
ASCII encodings, but instead represent strings encoded in the
ISO-8859-1/Latin-1 or ISO-8859-2/Latin-2 encodings.

These inconsistent encodings may prevent software from correctly
presenting or processing such files. Converting all source files to
valid UTF8 characters will ensure correct handling.

Comments written in Czech were replaced with lightly-corrected
translations from Google Translate. Additionally, comments describing
the proper handling of special characters were changed so that the
comments are now purely UTF8.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer
Amazon Web Services, Inc.
Co-authored-by: Andrew Hutchings <andrew@linuxjedi.co.uk>

trx_undo_page_report_rename(): Use the correct maximum length of
a table name. Both the database name and the table name can be up to
NAME_CHAR_LEN (64 characters) times 5 bytes per character in the
my_charset_filename encoding. They are not encoded in UTF-8!

fil_op_write_log(): Reserve the correct amount of log buffer for
a rename operation. The file name will be appended by
mlog_catenate_string().

rename_file_ext(): Reserve a large enough buffer for the file names.

take into account C/C specific CR_ERR_NET_WRITE error

MDEV-18873 Server crashes in Compare_identifiers::operator or in my_strcasecmp_utf8 upon ADD PERIOD IF NOT EXISTS with empty name

empty identifier specified as `` ends up with a NULL LEX_CSTRING::str in lexer.
This is not considered correct in upper layers, for example in Compare_identifiers::operator().
Empty column name is usually avoided by a check_column_name() call while parsing,
and period name matches the column name completely.
Hence, this fix uses the mentioned call for verification, too.

In commit 0b47c126 (MDEV-13542)
a few calls to mtr_t::memo_push() were moved before a write latch
on the page was acquired. This introduced a race condition:

1. is_block_dirtied() returned false to mtr_t::memo_push()
2. buf_page_t::write_complete() was executed, the block marked clean,
and a page latch released
3. The page latch was acquired by the caller of mtr_t::memo_push(),
and mtr_t::m_made_dirty was not set even though the block is in
a clean state.

The impact of this race condition is that crash recovery and backups
may fail.

btr_cur_latch_leaves(), btr_store_big_rec_extern_fields(),
btr_free_externally_stored_field(), trx_purge_free_segment():
Acquire the page latch before invoking mtr_t::memo_push().
This fixes the regression caused by MDEV-13542.

Side note: It would suffice to set mtr_t::m_made_dirty at the time
we set the MTR_MEMO_MODIFY flag for a block. Currently that flag is
unnecessarily set if a mini-transaction acquires a page latch on
a page that is in a clean state, and will not actually modify the block.
This may cause unnecessary acquisitions of log_sys.flush_order_mutex
on mtr_t::commit().

mtr_t::free(): If the block had been exclusively latched in this
mini-transaction, set the m_made_dirty flag so that the flush order mutex
will be acquired during mtr_t::commit(). This should have been part of
commit 4179f93d (MDEV-18976).
It was necessary to change mtr_t::free() so that
WriteOPT_PAGE_CHECKSUM::operator() would be able to avoid writing
checksums for freed pages.

Since the 10.5 split of the privileges, the required GRANTs
for various mariabackup operations has changed.

In the addition of tests, a number of mappings where incorrect:

The option --lock-ddl-per-table didn't require connection admin.

The option --safe-slave-backup requires SLAVE MONITOR even without
the --no-lock option.

This bug affected some queries with an IN/ALL/ANY predicand or an EXISTS
predicate whose subquery contained a GROUP BY clause that could be
eliminated. If this clause used a IN/ALL/ANY predicand whose left operand
was a single-value subquery then execution of the query caused a crash of
the server after invokation of remove_redundant_subquery_clauses().
The crash was caused by an attempt to exclude the unit for the single-value
subquery from the query tree for the second time by the function
Item_subselect::eliminate_subselect_processor().

This bug had been masked by the bug MDEV-28617 until a fix for the latter
that properly excluded units was pushed into 10.3.

Approved by Oleksandr Byelkin <sanja@mariadb.com>

buf_defer_drop_ahi(): Remove. Ever since
commit c7f8cfc9 (MDEV-27700)
it is safe to invoke btr_search_drop_page_hash_index(block, true)
to remove an orphan adaptive hash index.

Any attempt to upgrade page latches is prone to deadlocks. Recently,
we observed a few hangs that involved nothing more than a small table
consisting of one clustered index page, one secondary index page and
some undo pages.

followup for "remove invalid options from warning messages"

The issue is that trx_t::lock.was_chosen_as_deadlock_victim can be reset
before the transaction check it and set trx_t::error_state.

The fix is to reset trx_t::lock.was_chosen_as_deadlock_victim only in
trx_t::commit_in_memory(), which is invoked on full rollback. There is
also no need to have separate bit in
trx_t::lock.was_chosen_as_deadlock_victim to flag transaction it was
chosen as a victim of Galera conflict resolution, the same variable can be
used for both cases except debug build. For debug build we need to
distinguish deadlock and Galera's abort victims for debug checks. Also
there is no need to check for deadlock in lock_table_enqueue_waiting() for
Galera as the coresponding check presents in lock_wait().

Local variable "error_state" in lock_wait() was replaced with
trx->error_state, because before the replace
lock_sys_t::cancel<false>(trx, lock) and lock_sys.deadlock_check() could
change trx->error_state, which then could be overwritten with the local
"error_state" variable value.

The lock_wait_suspend_thread_enter DEBUG_SYNC point name is misleading,
because lock_wait_suspend_thread was eliminated in e71e6133. It was renamed
to lock_wait_start.

Reviewed by: Marko Mäkelä, Jan Lindström.

Removed use std::vector's ba push_back(), pop_back() to  make it more
obvious that memory in the vectors won't be reallocated.

Also, "borrowed" elements can be debugged a little better now,
they are put into the start of the m_cache vector.

This problem was earlier fixed by MDEV-27101.
Now adding UUID tests only.

MDEV-29319 Assertion failure size_in_header >= space.free_limit in fsp_get_available_space_in_free_extents()

- Don't remove the constant parameter in fsp_get_available_space_in_free_extents()

- InnoDB fts table initially added to LRU table cache
while creating the table. Later, table was marked
as non-evicted when we add the table to fts optimizer
list. Before marking the table as non-evicted, master
thread can try to evict the fts table.

MDEV-29319 Assertion failure size_in_header >= space.free_limit in fsp_get_available_space_in_free_extents()

- Race condition between fsp_get_available_space_in_free_extents()
and fsp_try_extend_data_file() while accessing space.free_limit.
Before calling fsp_get_available_space_in_free_extents(), take
shared lock on space->latch.

- Newly created InnoDB fulltext index does have only one column
and doesn't associate with primary key fields during DDL.
init_change_cols() has strict assertion that number of fields
should be greater than number of collation change columns.

Many Spider tests were broken by the merge commit, 36d173e5.

This reverts part of commit 212994f7
(MDEV-28974) and implements a better fix that works in that special case
while avoiding other failures.

fil_name_process(): Do not rename the tablespace in deferred_spaces;
it already contains the latest name for the space id.

deferred_spaces::create(): In mariadb-backup --prepare,
replace absolute data directory file path with short name
relative to the backup directory and store it as filename while
deferring tablespace file creation.

The index root page contains the fields BTR_SEG_TOP and BTR_SEG_LEAF
which keep track of allocated pages in the index tree. These fields
are normally protected by an Update latch, so that concurrent read
access to other parts of the page will be possible.

When the index root page is already exclusively latched in the
mini-transaction, we must not try to acquire a lower-grade Update latch.
In fact, when the root page is already X or U latched in the
mini-transaction, there is no point to acquire another latch.
Moreover, after a U latch was acquired on top of an X-latch,
mtr_t::defer_drop_ahi() would trigger an assertion failure or
lock corruption in block->page.lock.u_x_upgrade() because X locks
already exist on the block.

This problem may have been introduced in
commit 03ca6495 (MDEV-24142).

btr_page_alloc_low(), btr_page_free(): Initially buffer-fix the root page.
If it is already U or X latched, release the buffer-fix. Else, upgrade
the buffer-fix to a U latch.

mtr_t::u_lock_register(): Upgrade a buffer-fix to U latch.

mtr_t::have_u_or_x_latch(): Check if U or X latches are already
registered in the mini-transaction.

This problem was earlier fixed by MDEV-27101.
Adding INET6 tests only.