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.

Show outer_ref_condition in EXPLAIN FORMAT=JSON output.

Also fixed race condition in main.connect2 test: we need to wait for
disconnected connections to actually decrease Threads_connected.

This is expected to fix many test failures on 32bit builds where creation of
second temporary table was failing.

        --raw, --stop-never and --stop-never-slave-server-id=id options
        added to the mysqlbinlog tool.

This is an addition to rev. ed990465
Reverted some test cases changes done in MDEV-6150.

Cleanup now unused arguments of tdc_open_view().

Remove tdc_acquire_share() helpers: they don't actually make things simpler.