Replace wsrep_on() with trx_t::is_wsrep() where possible.

Also, rename some functions to member functions and
remove unused DBUG_EXECUTE_IF instrumentation:

trx_t::commit(): Renamed from trx_commit().

trx_t::commit_low(): Renamed from trx_commit_low().

trx_t::commit_in_memory(): Renamed from trx_commit_in_memory().

During the UPDATE of PRIMARY KEY columns, we may miscalculate the
size of the clustered index record.

row_upd_clust_rec_by_insert(): Pass the total number of off-page columns,
which may include such columns that were inherited from the record
and not created as part of the UPDATE operation.

This is based on
mysql/mysql-server@490c45e8c8e07197958dbb21214fd45ed668b559
which is a follow-up to
mysql/mysql-server@1fa475b85d24de4b9ce2958c0eed738c221fc82c
which we filed and fixed as MDEV-21511.

No test case was provided by Oracle.

INSERT...SELECT reading from an InnoDB table is slow due to
creating explicit record locks. Use the sequence engine instead.

Also, remove the space before rtr_page_need_second_split
to actually make the debug injection work.

when detecting running mysqld processes to stop,
ignore processes in different namespaces.

Several MYSQL_SYSVAR_STR parameters that employ both a validate
function callback fail to copy the string for saving the
validated value. The affected variables include the following:

innodb_ft_aux_table
innodb_ft_server_stopword_table
innodb_ft_user_stopword_table
innodb_buffer_pool_filename

The test case is an enhanced version of
mysql/mysql-server@0b0c30641fd66336e87394ac28587e40864f8af9
and the code changes are inspired by their fixes.

We are also importing and adjusting the test innodb_fts.stopword
to get coverage for the variable innodb_ft_user_stopword_table.

buf_dump(), buf_load(): Protect srv_buf_dump_filename with
LOCK_global_system_variables.

fts_load_user_stopword(): Minor cleanup

fts_load_stopword(): Remove the parameter global_stopword_table.

innobase_fts_load_stopword(): Protect innodb_server_stopword_table
against concurrent SET GLOBAL.

innodb_buffer_pool_evict_uncompressed(): Restart the loop when
prev_block might not enjoy mutex protection.

This is based on
mysql/mysql-server@eccaecac070b6747ecf14d6b9150791f8c3e8f6d

- Inplace alter shouldn't set default date column as '0000-00-00' when
table is not empty. So mysql_inplace_alter_table() copied
alter_ctx.error_if_not_empty to a new field of Alter_inplace_info.
In ha_innobase::check_if_supported_inplace_alter() should check the
error_if_not_empty flag and return INPLACE_NOT_SUPPORTED if the table
is not empty

lock

--ftwrl-wait-timeout does not finish mariabackup execution when acquired
backup lock can't be grabbed for the certain amount of time, it just
waits for a long queries finishing before acquiring the lock to avoid
unnecessary locking.

This commit extends --ftwrl-wait-timeout so, that mariabackup execution
is finished if it waits for backup lock during certain amount of time.

dict_stats_update_if_needed(): Replace the parameter THD*
with const trx_t& so that trx_t::is_wsrep() can be invoked
instead of the more expensive wsrep_on().

Replace also other occurrences of wsrep_on() with trx_t::is_wsrep().

The only change is a change of the version number.
As noted in commit 02af6278
there were no changes to InnoDB between MySQL 5.6.46 and 5.6.47
either.

The function wsrep_on() was being called rather frequently
in InnoDB and XtraDB. Let us cache it in trx_t and invoke
trx_t::is_wsrep() instead.

innobase_trx_init(): Cache trx->wsrep = wsrep_on(thd).

ha_innobase::write_row(): Replace many repeated calls to current_thd,
and test the cheapest condition first.

when opening the `user` table separately, reset `thd->open_tables`
for the duration of open, otherwise auto-repair fallback-and-retry
will close *all* tables (but reopen only `user`)

only use auth1 update (no "auth_or":[]) array, if there was no
"auth_or" array in the json yet.

support upgrades from 5.2 privilege tables

revert/simplify f5390eea

remove galera-specific checks from mtr and the main suite

fix embedded innodb_plugin tests

followup for 7198c6ab

Backport INSALL_SYMLINK cmake macro from 10.3.
It'll make libmysqlclient_r.* symlinks to link to the actual
shared library file, not to another symlink.

As a bonus it'll fix cmake warning about deprecated LOCATION property

This is a backport of the applicable part of
commit 93475aff and
commit 2c39f69d
from 10.4.

Before 10.4 and Galera 4, WSREP_ON is a macro that points to
a global Boolean variable, so it is not that expensive to
evaluate, but we will add an unlikely() hint around it.

WSREP_ON_NEW: Remove. This macro was introduced in
commit c863159c
when reverting WSREP_ON to its previous definition.

We replace some use of WSREP_ON with WSREP(thd), like it was done
in 93475aff. Note: the macro
WSREP() in 10.1 is equivalent to WSREP_NNULL() in 10.4.

Item_func_rand::seed_random(): Avoid invoking current_thd
when WSREP is not enabled.

_ma_fetch_keypage(): Correct an assertion that used to always hold.
Thanks to clang -Wint-in-bool-context for flagging this.

double_to_datetime_with_warn(): Suppress -Wimplicit-int-float-conversion
by adding a cast. LONGLONG_MAX converted to double will actually be
LONGLONG_MAX+1.

Since commit 7198c6ab
the ./mtr --embedded tests would fail to start innodb_plugin
because of an undefined reference to the symbol wsrep_log().

Let us define a stub for that function. The embedded server
is never built WITH_WSREP, but there are no separate storage
engine builds for the embedded server. Hence, by default,
the dynamic InnoDB storage engine plugin would be built WITH_WSREP
and it would fail to load into the embedded server library due to
a reference to the undefined symbol.

MDEV-18286 Assertion `pagecache->cnt_for_resize_op == 0' failed in
check_pagecache_is_cleaned_up on server shutdown

The reason for the crash is that the counter-of-pinned-pages in the
Aria pagecache goes wrong.
This only affects debug builds, as in these we do an assert on shutdown
if the counter-of-pinned-pages is not 0 (some page was left pinned).

The bug was that in 2 places in the page cache, when not succeeding to
pin a page and a retry was made, the counter-of-pinned-pages counter was
not properly adjusted.

In the given test case, BLOCK_COMMIT flushed all Aria files. If a block was flushed at the same time the insert tried to access it, the insert would retry to get the block and that would cause the counter to go wrong.

read TLS with my_thread_var
write TLS with set_mysys_var()

my_thread_var is no longer __attribute__ ((const)): this attribute
is simply incorrect here. Read gcc manual for more information.
sql/threadpool_generic.cc fails with that attribute.