trx_purge_truncate_rseg_history(): Add a parameter to specify if
the entire rollback segment is safe to be freed. If not, we may
still be able to invoke trx_undo_truncate_start() and free some pages.

trx_purge_free_segment(), trx_purge_truncate_rseg_history():
Replace some unreachable code with debug assertions.
A buffer-fix does prevent pages from being evicted
from the buffer pool; see buf_page_t::can_relocate().

Tested by: Matthias Leich

trx_purge_truncate_history(): Only call trx_purge_truncate_rseg_history()
if the rollback segment is safe to process. This will avoid leaking undo
log pages that are not yet ready to be processed. This fixes a regression
that was introduced in
commit 0de3be8c (MDEV-30671).

trx_sys_t::any_active_transactions(): Separately count XA PREPARE
transactions.

srv_purge_should_exit(): Terminate slow shutdown if the history size
does not change and XA PREPARE transactions exist in the system.
This will avoid a hang of the test innodb.recovery_shutdown.

Tested by: Matthias Leich

This is 11.0 part of the fix: in 11.0, get_costs_for_tables() calls
best_access_path() for all possible tables, for each call it saves
a POSITION object with the access method and "loose_scan_pos"
POSITION object.
The latter is saved even if there is no possible LooseScan plan. Saving
is done by copying POSITION objects which may generate a spurious
UBSan error.

Follow the approach taken in the rest of the test.

In Loose_scan_opt::save_to_position, initialize
POSITION::firstmatch_with_join_buf.

The code in create_internal_tmp_table() didn't take into account that
now temporary (derived) tables may have multiple indexes:

- one index due to duplicate removal
   = In this example created by conversion of big-IN(...) into subquery
   = this index might be converted into a "unique constraint" if the key
     length is too large.
- one index added by derived_with_keys optimization.

Make create_internal_tmp_table() handle multiple indexes.

Before this patch, use of a unique constraint was indicated in
TABLE_SHARE::uniques. This was ok as unique constraint was the only index
in the table. Now it's no longer the case so TABLE_SHARE::uniques is removed
and replaced with an in-memory-only flag HA_UNIQUE_HASH.

This patch is based on Monty's patch.
Co-Author: Monty <monty@mariadb.org>

Derived table creation code would call Field::make_new_field() which would
memcpy the Field object from the source table, including Field::read_stats.

But the temp. table as a whole had table->stats_is_read=false. Which was
correct but not consistent with Field::read_stats and caused an assertion.

Fixed by making sure that Field::read_stats=NULL for fields in the new
temporary (i.e. work) tables.

The problem, introduced in patch for MDEV-26301:

When check_join_cache_usage() decides not to use join buffer, it must
adjust the access method accordingly. For BNL-H joins this means switching
from pseudo-"ref access"(with index=MAX_KEY) to some other access method.

Failing to do this will cause assertions down the line when code that is
not aware of BNL-H will try to initialize index use for ref access with
index=MAX_KEY.

The fix is to follow the regular code path to disable the join buffer for
the join_tab ("goto no_join_cache") instead of just returning from
check_join_cache_usage().

because explicit_defaults_for_timestamp is now true

Do not try to decide merge/materialize for derived if it was already decided
(even if it is a view).

RocksDB (in a submodule) has to include <cstdint> to use uint64_t
but it doesn't. Until the submodule is upgraded, let's replace
problematic types with something that's available

select_insert::store_values() must reset
has_value_set bitmap before every row, just like mysql_insert() does.
because ON DUPLICATE KEY UPDATE and triggers modify it