disable tokudb paranoid asserts

Fix the bug properly (plugin cannot be unloaded as long as it's locked).
Enable and fix the test case.
Significantly reduce number of LOCK_plugin locks for semisync
(practically all locks were removed)

~40% bugfixed(*) applied
~40$ bugfixed reverted (incorrect or we're not buggy)
~20% bugfixed applied, despite us being not buggy
(*) only changes in the server code, e.g. not cmakefiles

mysql_derived_prepare() was executed on the statement memory.
Now it is executed on the runtime memory.
All bugs induced by this were fixed.

Fix for MDEV-6493: Assertion `table->file->stats.records > 0 || error' failure, or 'Invalid write' valgrind warnings, or crash on scenario with Aria table, view, LOCK TABLES

This bug only happens in case of paritioned tables used in LOCK TABLES and implicit_commit() was called
(as part of trying to execute a CREATE TABLE withing lock tables)

The problem was that Aria could not move the tables from one transaction to the new one, as thd->open_tables contained
a partitioned tables and not an Aria table.

Fix:
- Store a list of all open tables that are part of a share in share->open_tables
- In maria::implict_commit() use transaction->used_tables & share->open_tables to find out which tables
  was part of the current transaction instead of using thd->open_tables, which may contain partitioned tables.


mysql-test/suite/maria/maria_partition.result:
  Added test case
mysql-test/suite/maria/maria_partition.test:
  Added test case
storage/maria/ha_maria.cc:
  Use trn->used tables and share->open_tables to find out which tables was part of the current transaction instead of using thd->open_tables.
storage/maria/ma_close.c:
  Remove closed table from share->open_list
storage/maria/ma_open.c:
  Add table to share->open_list
storage/maria/ma_state.c:
  Added comment
storage/maria/maria_def.h:
  Added share->open_list, a list of all tables that is using this share.

* remove incorrect assertion (it didn't take into account concurrent clients)
* fix the comment

Free the trx of the current thd (if any) in innobase_end()

MDEV-6302 Wrong result set when using GROUP BY FROM_UNIXTIME(...)+0
Fixed.

  
- adjusted a test result according to the change made for MDEV-6100;
- added explicit timezone for engines/iuds, since MTR in
  MariaDB does not set it like MySQL's, and tests with constant TIMESTAMP
  can have different outcome

MDEV-6082 Assertion `0' fails in TC_LOG_DUMMY::log_and_order on DML after installing TokuDB at runtime on server with disabled InnoDB

We don't support changing tc_log implementation at run time.
If the first XA-capable engine is loaded with INSTALL PLUGIN - disable its
XA capabilities with a warning

abort the wait loop if mysqld_safe is not running

InnoDB: Failing assertion: mutex_own(&buf_pool->LRU_list_mutex)

and

InnoDB: Assertion failure in thread 2868898624 in file buf0lru.c line 1077
InnoDB: Failing assertion: mutex_own(&buf_pool->LRU_list_mutex)

Analysis: Function buf_LRU_free_block might release LRU_list_mutex on
same cases to avoid mutex order problems, we need to take it back 
before accessing list. 

backport from 10.0 the fix for:
  MDEV-5756 CMake option to build without thread pool

issue an error for unrecognized options in the [mysqld_safe] section of my.cnf
but don't abort the script

KILL USER should ignore system threads where sctx->user=sctx->host=NULL

fix by Sriram Patil

IBUF_DUMMY table.

compression failures on insert buffer.

MySQL Bug#71095: Wrong results with PARTITION BY LIST COLUMNS()
MySQL Bug#72803: Wrong "Impossible where" with LIST partitioning
MDEV-6240: Wrong "Impossible where" with LIST partitioning
- Backprot the fix from MySQL Bug#71095.

- When traversing JOIN_TABs with first_linear_tab/next_linear_tab(), don't forget
  to enter the semi-join nest when it is the first table in the join order.
  Failure to do so could cause e.g. I_S tables not to be filled.

Item_func_min_max::get_date() did not clear ltime->year when returning a TIME value.

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