MDEV-21971 Bind BINLOG ADMIN to binlog_annotate_row_events and binlog_row_image global and session variables

MDEV-21969 Bind REPLICATION SLAVE ADMIN to relay_log_*, sync_master_info, sync_relay_log, sync_relay_log_info

Problem was that replace_dynstr_append_mem() assumed strings are
null terminated which is not always the case.

Simplifying definitions on Sys_var_charptr*:

- Removing sys_var::is_os_charset
- Adding a new class Sys_var_charptr_fscs, to handle system
  variables with character_set_filesystem.

           'index_merge_sort_union=off'

When index_merge_sort_union is set to 'off' and  index_merge_union is set
to 'on' then any evaluated index merge scan must consist only of ROR scans.
The cheapest out of such index merges must be chosen. This index merge
might not be the cheapest index merge.

This was to remove a performance regression between 10.3 and 10.4
In 10.5 we will have a better implementation of records_in_range
that will enable us to get more statistics.
This change was not done in 10.4 because the 10.5 will be part of
a larger change that is not suitable for the GA 10.4 version

Other things:
- Changed default handler block_size to 8192 to fix things statistics
  for engines that doesn't set the block size.
- Fixed a bug in spider when using multiple part const ranges
  (Patch from Kentoku)

Move function ut_crc32_swap_byteorder to a non-x86 #ifdef area.

As its only used in BIGENDIAN, use #ifdefs around
ut_crc32_swap_byteorder.

Travis CI and Debian both include s390x in builds/test, which is big endian.

Fixes commit: 1312b4eb

It did not work, eventhough the default for Windows was changed to 1
for the corresponding system variable.
This be because  test_flags was zeroed mysql_init_variables.

The patch fixes this glitch.

log_write_buf(): Remove the unused variable write_header.
The dependent code was removed in
commit 0c2365c4.
That was dead or unnecessary code at least ever since
commit 9ef2d29f
removed the support for innodb_log_files_in_group>1.

mi_records_in_range(): Because HA_POS_ERROR cannot be accurately
represented in double (it will be off by one), add an explicit
cast to silence the warning.

log_t::has_encryption_key_rotation(): checks whether
key rotation is supported.

In a subsequent redo log format version, this key rotation
may be broken again.

Write log header just ones when file is created, instead of
writing to it on every log file wrap around.

log_t::file::write_header_durable(): this one writes to log header

log_write_buf(): this one stops writing to log header

move statistics modification into one place

restore check for client charset_info == NULL, which was previously
removed in MDEV-8844

that by a (un)lucky coincidence did not prevent 8fd654ce
from working properly

when selecting from perfschema, filter out statements
used by the test istself in wait_condition.inc, because they,
by design, can be repeated unpredictable number of times.

By default, when redo log is being written for modifying a persistent
data page, the data page must actually be changed. If the write can
sometimes be optimized away, then the template parameter w=mtr_t::OPT
should be passed in order to silence the debug assertion failure.

InnoDB undo log pages can be reused without properly freeing or
initializing them in between. In particular, the undo log header
page field TRX_UNDO_TRX_NO could have been part of an undo log
record page, and those bytes could accidentally have the desired
value when the page is reused as an undo log header page of
another transaction.

Because the function trx_undo_set_state_at_finish() always changes
the TRX_UNDO_STATE of the page, and because recovery is only reading
TRX_UNDO_TRX_NO for pages that either have the correct TRX_UNDO_STATE
or, in trx_rseg_array_init(), are attached to the TRX_SYS page, the
garbage values in TRX_UNDO_TRX_NO do not seem to cause a problem.

This assertion failure affects debug builds only.

Force correct PCRE2 linking in the official binaries.
System pcre2 in RPM/DEB, bundled in bintars.

fix build requirements for debian

strip all client binaries (that is, not mysqld) in bintars

in mysql_release builds only build embedded for rpm and deb
but not for bintar