Added --thread_cache_size=0 to some tests that was depending on not having
a thread cache.

Added --thread_cache_size=0 to slow_launch_time_func.test as otherwise
the new thread would start too fast to be counted as a slow_launch_thread.

between gbk_chinese_ci and big5_chinese_ci.

> commit e0929951
> Author: Alexander Barkov <bar@mariadb.org>
> Date:   Wed Mar 16 10:55:12 2016 +0400
>
>     MDEV-9665 Remove cs->cset->ismbchar()
>     Using a more powerfull cs->cset->charlen() instead.

Added 5 minute timeout before automaticlally removing threads from thread
cache.

This solves a problem with jemalloc, which is slow with a small
thread cache and also makes thread_cache big enough that most users
doesn't have to touch it

filesort and init_read_record() for the same table.
This will simplify code for WINDOW FUNCTIONS (MDEV-6115)

- Filesort_info renamed to SORT_INFO and moved to filesort.h
- filesort now returns SORT_INFO
- init_read_record() now takes a SORT_INFO parameter.
- unique declaration is moved to uniques.h
- subselect caching of buffers is now more explicit than before
- filesort_buffer is now reusable even if rec_length has changed.
- filsort_free_buffers() and free_io_cache() calls are removed
- Remove one malloc() when using get_addon_fields()

Other things:
- Added --debug-assert-on-not-freed-memory option to make it easier to
  debug some not-freed-memory issues.

Fix of status variable name and order.

The actual patch with this name neglected to update a test result. Fixing.

Its value changes depending on the parser constants, so it changes
every time somebody makes a change in the parser

Now we do not swap buffers back but just free old one.

Support of "previuousely used statement ID".
All IDs with highest bit ON reserved for special use.

simple COM_MULTI support (no prepared statements chain yet).

Adding a command from the end of avaliable commands numering space (254)

Using a more powerfull cs->cset->charlen() instead.

Do not try to send progress packets if client was not informed about them.

MDEV-4102 Limitation on DOUBLE or REAL length is ignored with INSERT .. SELECT

* Maintain coding style in sql_yacc.yy in regards to optional clauses.
* Remove unused variable from sql_acl.cc.
* Update test case

Update test to account for the new SHOW CREATE USER command.

Adding an extra statement requires test cases update.

Implemented the alter user syntax. Also tested that create user
creates users accordingly.

Extend the syntax accepted by the grammar to account for the new create user
and alter user syntax.

Simplified audit event dispatching call chain from:
  mysql_audit_notify_connection_connect() // can be inlined
  mysql_audit_notify()                    // can't be inlined
  connection_class_handler()              // can't be inlined
  event_class_dispatch()                  // can be inlined
  plugins_dispatch()                      // can be inlined
  plugin->event_notify()                  // can't be inlined
to:
  mysql_audit_notify_connection_connect() // can be inlined
  mysql_audit_notify()                    // can't be inlined
  plugins_dispatch()                      // can be inlined
  plugin->event_notify()                  // can't be inlined

In RHEL7/RHEL7.1 libcrack behavior seem to have been modified so that
"foobar" password is considered bad (due to descending "ba") earlier than
expected. For details google for cracklib-2.9.0-simplistic.patch.

Adjusted affected passwords not to have descending and ascending sequences.