Problem:
========
SHOW BINLOG EVENTS FROM <pos> reports following assert when ASAN is enabled.

Rows_log_event::Rows_log_event(const char*, uint,
    const Format_description_log_event*):
Assertion `var_header_len >= 2'

Implemented part of upstream patch.
commit: mysql/mysql-server@a3a497ccf7ecacc900551fb1e47ea4078b45c351

Fix:
===
**Part2: Avoid reading out of buffer limits**

Problem:
========
SHOW BINLOG EVENTS FROM <pos> causes a variety of failures, some of which are
listed below. It is not a race condition issue, but there is some
non-determinism in it.

Analysis:
========
"show binlog events from <pos>" code considers the user given position as a
valid event start position. The code starts reading data from this event start
position onwards and tries to map it to a set of known events. Each event has
a specific event structure and asserts have been added to ensure that read
event data satisfies the event specific requirements. When a random position
is supplied to "show binlog events command" the event structure specific
checks will fail and they result in assert.

Fix:
====
The fix is split into different parts. Each part addresses either an ASAN
issue or an assert/crash.

**Part1: Checksum based position validation when checksum is enabled**


Using checksum validate the very first event read at the user specified
position. If there is a checksum mismatch report an appropriate error for the
invalid event.

Moved to the next problematic year (2038).

For Item_direct_view_ref , get value from val_* methods
instead of result* family
The val_* methods gets value from the item on which it is referred.

MDEV-19680:: Assertion `!table || (!table->read_set || bitmap_is_set(table->read_set, field_index) || (!(ptr >= table->record[0] && ptr < table->record[0] + table->s->reclength)))' or alike failed upon SELECT with mix of functions from simple view

Set read_set bitmap for view from the JOIN::all_fields list instead of JOIN::fields_list
as split_sum_func would have added items to the all_fields list.

in 10.1+ one should use

MY_CHECK_AND_SET_COMPILER_FLAG("-Wno-address-of-packed-member")

and it's already done in storage/tokudb/PerconaFT/CMakeLists.txt

Item_ref::val_(datetime|time)_packed() erroneously called
(*ref)->val_(datetime|time)_packed().

- Fixing to call (*ref)->val_(datetime|time)_packed_result().
- Backporting Item::val_(datetime|time)_packed_result() from 10.3.
- Fixing Item_field::get_date_result() to handle null_value in the same
  way how Item_field::get_date() does.

do not fallback to malloc(), always return properly aligned buffer

One may not call memcpy(dst, src=NULL, size), even if size==0.

Remove Query_tables_list::lock_tables_state - it is not used and it causes
errors like this:

sql_lex.h:1675:7: runtime error: load of value 2779096485, which is not a
valid value for type 'enum_lock_tables_state'

Fix wrong typecast

Fixed the condition for waking up/creating another thread.

If there is some work to do (if the request queue is not empty),
a thread should be woken or created.

The condition was incorrect since 18c9b345

crashes on Debian 10

Problem:
=======
Test "binlog.binlog_parallel_replication_marks_row" fails sporadically due to
result length mismatch.

Analysis:
=========
Test generates a binary log and it looks for certain words within the binary
log file and prints them. For example word like "GTID,BEGIN,COMMIT ...".
Binary log output contains base64 encoded characters. Occasionally the encoded
characters match with the above words and results in test failure.

+XwoFWxMBAAAALgAAAGEDAAAAAB8AAAAAAAEABHRlc3QAAnQxAAIDAwACFGTIDQ==
+AAAAAAAAAAAEEwQADQgICAoKCgGTIDw9

Fix:
===
Improve the regular expression to match exact words.

Let MTR check for error existence after running a test and return it back to user.

Error reporting itset might be much better, but first of all we need to see that
something went wrong.

wsrep_on parameter can be visible even when wsrep_on is set OFF
so we need to check variable_value from I_S also.

Set an explicit start and stop timeout of 900 seconds for the
MariaDB Server systemd service

Set an explicit start and stop timeout of 900 seconds for the
MariaDB Server systemd service

It is C++, not Java, the order of includes is often important.

It is C++, not Java, the order of includes is often important.

The lintian Debian tool is complaining about:
  'W: mariadb-test: manpage-has-errors-from-man
  usr/share/man/man1/mysql-test-run.pl.1.gz 246: warning [p 2, 6.0i, div
  '3tbd1,1', 0.3i]: can't break line'

See: https://salsa.debian.org/faust-guest/mariadb-10.3/-/jobs/431900

The following command permits to catch the problematic lines:
  $ groff -man -Tascii ./mysql-test-run.pl.1 | less

Closes #1419

$glob_mysql_test_dir was the wrong directory for strace output as
it was for in-tree builds only so failed for:
* out of tree builds
* --parallel; and
* --mem

strace output wasn't saved.

strace-option never replaced existing arguments (so ammended
documentation).

strace-client didn't accept an argument as described.

Replaced specification of client with this with 'stracer' to be
consistent with --debugger option.

For consistency with debugger options, --client-strace was added to
execute the strace on the mysqltest.

Example: Running one test

$ ./mtr --strace --client-strace funcs_1.is_table_constraints
Logging: ./mtr  --strace --client-strace funcs_1.is_table_constraints
vardir: /home/anel/mariadb/5.5/mysql-test/var
Checking leftover processes...
Removing old var directory...
 - WARNING: Using the 'mysql-test/var' symlink
Creating var directory '/home/anel/mariadb/5.5/mysql-test/var'...
Checking supported features...
MariaDB Version 5.5.67-MariaDB-debug
Installing system database...
 - SSL connections supported
 - binaries are debug compiled
Collecting tests...

==============================================================================

TEST                                      RESULT   TIME (ms) or COMMENT
--------------------------------------------------------------------------

worker[1] Using MTR_BUILD_THREAD 300, with reserved ports 16000..16019
funcs_1.is_table_constraints             [ pass ]   1270
--------------------------------------------------------------------------
The servers were restarted 0 times
Spent 1.270 of 3 seconds executing testcases

Completed: All 1 tests were successful

$ find -L . -name \*strace -ls
      653     56 -rw-r--r--   1 anel     anel        57147 Nov 29 15:08 ./var/log/mysqltest.strace
      646   1768 -rw-r--r--   1 anel     anel      1809855 Nov 29 15:08 ./var/log/mysqld.1.strace

Example: Running test in parallel

$ mysql-test/mtr --strace --client-strace  --mem --parallel=3  main.select
Logging: /home/dan/software_projects/mariadb-server/mysql-test/mysql-test-run.pl  --strace --client-strace --mem --parallel=3 main.select
vardir: /home/dan/software_projects/build-mariadb-10.3/mysql-test/var
Checking leftover processes...
Removing old var directory...
Creating var directory '/home/dan/software_projects/build-mariadb-10.3/mysql-test/var'...
 - symlinking 'var' to '/dev/shm/var_auto_0v2E'
Checking supported features...
MariaDB Version 5.5.67-MariaDB
 - SSL connections supported
Collecting tests...
Installing system database...

==============================================================================

TEST                                  WORKER RESULT   TIME (ms) or COMMENT
--------------------------------------------------------------------------

worker[1] Using MTR_BUILD_THREAD 300, with reserved ports 16000..16019
worker[3]  - 'localhost:16040' was not free
worker[2] Using MTR_BUILD_THREAD 301, with reserved ports 16020..16039
worker[3] Using MTR_BUILD_THREAD 303, with reserved ports 16060..16079
main.select                              w1 [ pass ]   7310
--------------------------------------------------------------------------
The servers were restarted 0 times
Spent 7.310 of 11 seconds executing testcases

Completed: All 1 tests were successful.

$ find mysql-test/var/ -name \*strace -ls
  5213766   1212 -rw-r--r--   1  dan      dan       1237817 May 20 16:47 mysql-test/var/1/log/mysqltest.strace
  5214733  13016 -rw-r--r--   1  dan      dan      13328335 May 20 16:47 mysql-test/var/1/log/mysqld.1.strace

$ mysql-test/mtr --strace --client-strace --strace-option='-e' --strace-option='trace=openat'  --mem --parallel=3  main.select
...
$ find mysql-test/var/ -name \*strace -ls
  5220790      8 -rw-r--r--   1  dan      dan          6291 May 20 17:02 mysql-test/var/3/log/mysqltest.strace
  5224140    308 -rw-r--r--   1  dan      dan        314356 May 20 17:02 mysql-test/var/3/log/mysqld.1.strace
$ more mysql-test/var/3/mysqltest.strace
1692  openat(AT_FDCWD, "/home/dan/software_projects/mariadb-server/libmysql/.libs/tls/x86_64/x86_64/libpthread.so.0", O_RDONLY|O_CLOEXEC) =
-1 ENOENT (No such file or directory)
1692  openat(AT_FDCWD, "/home/dan/software_projects/mariadb-server/libmysql/.libs/tls/x86_64/libpthread.so.0", O_RDONLY|O_CLOEXEC) = -1 ENOE
NT (No such file or directory)

Closes #600

init_settings.keywords and it's pointee are shared data. Protect them
with mutex too.