Tests for MDEV-18892 failed, because of extra 'Prepare' and 'Close stmt'
entries in the output.

Filtering out PS related entries (where it is necessary).

Adding an intermediate volatile variable to avoid using co-processor registers
on some platforms (e.g. 32-bit x86).
This change makes test results stable accross all platforms.

Idea is that many users do not install galera library and do not want
to unnecessary run galera and wsrep suites. Furthermore, failures on
these suites disturb development as buildbot shows red failing column
and causes unnecessary work for those who do not care galera tests.
There will be other way to run these suites on buildbot.

When there is a huge transaction in the undo log, the purge threads
may get stuck in trx_purge_attach_undo_recs() for a long time,
causing the server to hang on a normal shutdown (innodb_fast_shutdown>0).

Apparently the innodb_purge_batch_size does not work correctly, or the
n_pages_handled is not being incremented correctly. We do not fix that
for now, but we will instead check if shutdown has been initiated,
allowing the purge threads to shut down without delays.

MDEV-16958 Assertion `field_length < 5' failed in Field_year::val_str or data corruption upon SELECT with UNION and aggregate functions

If an IN-subquery is used in a table-less select the current code
should never consider it as candidate for semi-join optimizations.
Yet the function check_and_do_in_subquery_rewrites() improperly
checked the property "to be a table-less select". As a result
such select in IN subquery was used in INSERT .. SELECT then
the IN subquery by mistake was registered as a semi-join subquery
and convert_subq_to_sj() was called for it. However the code of
this function does not assume that the parent select of the subquery
could be a table-less select.

There were two newly enabled warnings:
1. cast for a function pointers. Affected sql_analyse.h, mi_write.c
   and ma_write.cc, mf_iocache-t.cc, mysqlbinlog.cc, encryption.cc, etc

2. memcpy/memset of nontrivial structures. Fixed as:
* the warning disabled for InnoDB
* TABLE, TABLE_SHARE, and TABLE_LIST got a new method reset() which
  does the bzero(), which is safe for these classes, but any other
  bzero() will still cause a warning
* Table_scope_and_contents_source_st uses `TABLE_LIST *` (trivial)
  instead of `SQL_I_List<TABLE_LIST>` (not trivial) so it's safe to
  bzero now.
* added casts in debug_sync.cc and sql_select.cc (for JOIN)
* move assignment method for MDL_request instead of memcpy()
* PARTIAL_INDEX_INTERSECT_INFO::init() instead of bzero()
* remove constructor from READ_RECORD() to make it trivial
* replace some memcpy() with c++ copy assignments

Tests for MDEV-18667 ASAN heap-use-after-free in make_date_time / Arg_comparator::compare_string / Item_func_nullif::compare

The patch for MDEV-14926 fixed MDEV-18667 as well. Adding tests only.

MDEV-14926 AddressSanitizer: heap-use-after-free in make_date_time on weird combination of functions

If wsrep provider (i.e. galera library) is defined but wsrep_on=OFF
we should not force row binlog row format.

The patch for MDEV-15945 fixed MDEV-18892. Adding tests only.

Make mysqltest to use --ps-protocol more

use prepared statements for everything that server supports
with the exception of CALL (for now).

Fix discovered test failures and bugs.

tests:
* PROCESSLIST shows Execute state, not Query
* SHOW STATUS increments status variables more than in text protocol
* multi-statements should be avoided (see tests with a wrong delimiter)
* performance_schema events have different names in --ps-protocol
* --enable_prepare_warnings

mysqltest.cc:
* make sure run_query_stmt() doesn't crash if there's
  no active connection (in wait_until_connected_again.inc)
* prepare all statements that server supports

protocol.h
* Protocol_discard::send_result_set_metadata() should not send
  anything to the client.

sql_acl.cc:
* extract the functionality of getting the user for SHOW GRANTS
  from check_show_access(), so that mysql_test_show_grants() could
  generate the correct column names in the prepare step

sql_class.cc:
* result->prepare() can fail, don't ignore its return value
* use correct number of decimals for EXPLAIN columns

sql_parse.cc:
* discard profiling for SHOW PROFILE. In text protocol it's done in
  prepare_schema_table(), but in --ps it is called on prepare only,
  so nothing was discarding profiling during execute.
* move the permission checking code for SHOW CREATE VIEW to
  mysqld_show_create_get_fields(), so that it would be called during
  prepare step too.
* only set sel_result when it was created here and needs to be
  destroyed in the same block. Avoid destroying lex->result.
* use the correct number of tables in check_show_access(). Saying
  "as many as possible" doesn't work when first_not_own_table isn't
  set yet.

sql_prepare.cc:
* use correct user name for SHOW GRANTS columns
* don't ignore verbose flag for SHOW SLAVE STATUS
* support preparing REVOKE ALL and ROLLBACK TO SAVEPOINT
* don't ignore errors from thd->prepare_explain_fields()
* use select_send result for sending ANALYZE and EXPLAIN, but don't
  overwrite lex->result, because it might be needed to issue execute-time
  errors (select_dumpvar - too many rows)

sql_show.cc:
* check grants for SHOW CREATE VIEW here, not in mysql_execute_command

sql_view.cc:
* use the correct function to check privileges. Old code was doing
  check_access() for thd->security_ctx, which is invoker's sctx,
  not definer's sctx. Hide various view related errors from the invoker.

sql_yacc.yy:
* initialize lex->select_lex for LOAD, otherwise it'll contain garbage
  data that happen to fail tests with views in --ps (but not otherwise).

This solves the following issues:

* unlike lex->m_sql_cmd and lex->sql_command, thd->query_plan_flags
  is not reset in Prepared_statement::execute, it survives
  till the log_slow_statement(), so slow logging behaves correctly in --ps

* using thd->query_plan_flags for both slow_log_filter and
  log_slow_admin_statements means the definition of "admin" statements
  for the slow log is the same no matter how it is filtered out.

Added metadate info after prepare EXPLAIN/ANALYZE.

Prepare os ANALYZE now respond as EXPLAIN.

row_merge_create_fts_sort_index(): Initialize dict_col_t in
an unambiguous way. GCC 6 and later appear to be able to optimize
away the memset() that is part of mem_heap_zalloc() in the
placement new call. Let us avoid using placement new in order
to ensure that the objects will actually be initialized.

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71388

https://gcc.gnu.org/ml/gcc/2016-02/msg00207.html

While the latter reference hints that the optimization is only
applicable to non-POD types (and dict_col_t does not define
any member functions before 10.2), it is most consistent to
use the same initialization across all versions.

ALTER TABLE ... ADD FOREIGN KEY may trigger assertion failure when
it has LOCK=EXCLUSIVE clause or concurrent FLUSH TABLES is being
executed.

In both cases being altered table is marked as flushed, which forces
subsequent attempt to open parent table to re-open. Which in turn is
not allowed while transaction is running.

Rather than opening parent table, just take appropriate MDL lock.

Also removed table_already_fk_prelocked() check: MDL itself has much
better methods to handle duplicate locks. E.g. the former won't acquire
MDL_SHARED_NO_WRITE if it already has MDL_SHARED_READ.

This can be useful:
UBSAN_OPTIONS=log_path=/some/path

clang users may want to increase stack size in include/my_pthread.h or enable
some optimizations

Clean up after commit 0957d257
which introduced some disorder (unsorted or duplicated test names).

modified:   suite/galera/t/galera_autoinc_sst_mariabackup.test

remove WSREP_SST_OPT_SUFFIX_VALUE, checking [mysqld] is covered in the parse_cnf --mysqld case also in wsrep_sst_xtrabackup-v2

wsrep_sst: remove WSREP_SST_OPT_SUFFIX_VALUE, checking [mysqld] is covered in the parse_cnf --mysqld case

modified:   mysql-test/suite/galera/disabled.def
modified:   mysql-test/suite/galera/r/galera_many_rows.result
modified:   mysql-test/suite/galera/t/galera_kill_nochanges.test
new file:   mysql-test/suite/galera/t/galera_many_rows.cnf
modified:   mysql-test/suite/galera/t/galera_many_rows.test
modified:   mysql-test/suite/galera/t/galera_var_dirty_reads.test
modified:   scripts/wsrep_sst_mariabackup.sh

galera.partition and galera.galera_binlog_stmt_autoinc regularly display
mismatching values for AUTO_INCREMENT columns.

galera.MW-336 often times out while waiting for something in PROCESSLIST.

Also, sort the test names, remove the redundant "galera." prefix and
fix typos in 2 test names.