Updated --help text to declare --slave-parallel-threads as an alpha feature

mysql-test/r/mysqld--help.result:
  Updated --help text
sql/slave.cc:
  Added missing trans_retries++ that caused rpl_deadlock_innodb.test to fail.
  This is safe as this part is never run in parallel.
sql/sql_base.cc:
  Fixed temporary table handling (part of merge)
sql/sys_vars.cc:
  Updated --help text to declare --slave-parallel-threads as an alpha feature

10.0 part of the task, fix system tables

fix tests to clean up properly

according to one of the recent changes.

The merge is still missing a few hunks related to temporary tables and
InnoDB log file size. The associated code did not seem to exist in
10.0, so the merge of that needs more work. Until this is fixed, there
are a number of test failures as a result.

For compatibility purposes let InnoDB use DATA_INT for MYSQL_TYPE_ENUM and MYSQL_TYPE_SET.
Silence the warning for these types and let the index translation table to be built anyway.

Test case by Jeremy Cole.

In parallel replication, there are two kinds of events which are
executed in different ways.

Normal events that are part of event groups/transactions are executed
asynchroneously by being queued for a worker thread.

Other events like format description and rotate and such are executed
directly in the driver SQL thread.

If the direct execution of the other events were to update the old-style
position, then the position gets updated too far ahead, before the normal
events that have been queued for a worker thread have been executed. So
this patch adds some special cases to prevent such position updates ahead
of time, and instead queues dummy events for the worker threads, so that
they will at an appropriate time do the position updates instead.

(Also fix a race in a test case that happened to trigger while running
tests for this patch).

which makes it possible to add more world language collations
with very complex collation rules (e.g. Myanmar):
- Weight string for a single character in a user defined collation
  was erroneously limited to 7 weights (instead of 8 weights).
  Added an extra element in the user-defined weight arrays,
  to fit 8 non-zero weights.
- Weight string limit for contractions was made two times longer (16 weights),
  which allows longer contractions without affecting the performance
  of filesort.
- A user-defined collation now refuses to initialize and reports an error
  in case if a weight string gets longer than 8 weights for a single character,
  or longer than 16 weights for a contraction. Previously weight strings
  for such characters (and contractions) were cut, so a collation
  could silently start with wrong rules.
- Fixed a bug in handling rules like "&a << b" in combination with
  shift-after-method="expand". The primary weight for "b" was not
  correctly calculated, which erroneously made "b" primary greater than "a"
  instead of primary equal to "a".

MDEV-4736 - Assertion `! is_set()' fails in Diagnostics_area::set_ok_status on
            UPDATE which violates constraint on a remote table

MDEV-5196: Server hangs or assertion `!thd->wait_for_commit_ptr' fails on MASTER_POS_WAIT with slave-parallel-threads > 0

Fix a couple of issues in MDEV-4506, Parallel replication:

 - Missing mysql_cond_signal(), which could cause hangs.

 - Fix incorrect update of old-style replication position.

 - Change assertion to error handling (can trigger on manipulated/
   corrupt binlog).

  
  There was 2 problems:
  1) coping/moving of the same type (usually casting) as sizeof() (solved in different ways depends on the cause);
  2) using 'const' in SSL_CTX::getVerifyCallback() which return object (not reference) and so copy of the object will be created and 'const' has no sens.

In parallel replication, when the IO thread switches relay log,
the SQL thread re-opens the current relaylog and seeks to the
current position. There was a race that would cause it to
sometimes seek to the wrong position, causing corruption and
crash.

Analysis:
st_select_lex_unit::prepare() computes can_skip_order_by as TRUE.
As a result join->prepare() gets called with order == NULL, and
doesn't do name resolution for the inner ORDER clause. Due to this
the prepare phase doesn't detect that the query references non-exiting
function and field.
  
Later join->optimize() calls update_used_tables() for a non-resolved
Item_field, which understandably has no Field object. This call results
in a crash.

Solution:
Resolve unnecessary ORDER BY clauses to detect if they reference non-exising
objects. Then remove such clauses from the JOIN object.

MDEV-5189: Error handling in parallel replication.

Fix error handling in parallel worker threads when a query fails:

 - Report the error to the error log.

 - Return the error back, and set rli->abort_slave.

 - Stop executing more events after the error.

  GRANT ... IDENTIFIED BY [ PASSWORD ] ...
  GRANT ... IDENTIFIED VIA ... [ USING ... ]
  GRANT ... REQUIRE ...
  GRANT ... MAX_xxx ...
  SET PASSWORD FOR ... = ...

modified:
  storage/connect/ha_connect.cc
  storage/connect/odbconn.cpp
  storage/connect/odbconn.h

  Fix option other ignored when parsing URL

modified:
  storage/connect/ha_connect.cc
  storage/connect/mysql-test/connect/t/mysql.test
  storage/connect/mysql-test/connect/t/mysql_grant.test
  storage/connect/tabmysql.cpp
  storage/connect/tabmysql.h

modified:
  storage/connect/ha_connect.cc
  storage/connect/myconn.h
  storage/connect/tabmysql.cpp
  storage/connect/tabmysql.h