Fix mariabackup to crash if opening tablespace fails, insitead of
continuing after an error.

In a Ubuntu Xenial build environment, the compiler identified as
g++-5.real (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0 20160609
seems to be emitting incorrect code for the compilation unit
trx0rec.cc, triggering a bogus-looking AddressSanitizer report
of an invalid read of something in the function trx_undo_rec_get_pars().
This is potentially affecting any larger tests where the InnoDB
purge subsystem is being exercised.

When the optimization level of trx0rec.cc is limited to -O1, no
bogus failure is being reported. With -O2 or -O3, a lot of things
seemed to be inlined in the function, and the disassembly of the
generated code did not make sense to me.

Item_cond::eval_not_null_tables(): Use Item::eval_const_cond(),
just like Item_cond::fix_fields().

This inconsistency was found while merging to 10.3, where the
Microsoft compiler is configured to report an error for comparing
longlong to bool.

Before MDEV-12113 (MariaDB Server 10.1.25), on shutdown InnoDB would write
the current LSN to the first page of each file of the system tablespace.
This is incompatible with MariaDB's InnoDB table encryption, because
encryption repurposed the field for an encryption key ID and checksum.

buf_page_is_corrupted(): For the InnoDB system tablespace, skip
FIL_PAGE_FILE_FLUSH_LSN when checking if a page is all zero,
because the first page of each file in the system tablespace can
contain nonzero bytes in the field.

By applying 7bd258c4.

unfortunately, the year 2038 problem prevented me from pushing
the deadline even further into the future.

The 'bitmap_dir' has to be closed when no longer needed

Simulate slow statements only for COM_QUERY and COM_STMT_EXECUTE commands,
to exclude mysqld_stmt_prepare() and mysqld_stmt_close() entries from the log,
as they are not relevant for log_slow_debug.test. This simplifies the test.

Fixed issue in logic.

The file will be closed on line 540

swap two lines

Corrected one more "refering" typo.

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.