Add a test case for killing a waiting query in parallel replication.

Fix several bugs found:

 - We should not wakeup_subsequent_commits() in ha_rollback_trans(), since we
   do not know the right wakeup_error() to give.

 - When a wait_for_prior_commit() is killed, we must unregister from the
   waitee so we do not race and get an extra (non-kill) wakeup.

 - We need to deal with error propagation correctly in queue_for_group_commit
   when one thread is killed.

 - Fix one locking issue in queue_for_group_commit(), we could unlock the
   waitee lock too early and this end up processing wakeup() with insufficient
   locking.

 - Fix Xid_log_event::do_apply_event; if commit fails it must not update the
   in-memory @@gtid_slave_pos state.

 - Fix and cleanup some things in the rpl_parallel.cc error handling.

 - Add a missing check for killed in the slave sql driver thread, to avoid a
   race.

A couple of more parallel replication waits made killable.

Make wait_for_prior_commit killable, and handle the error if
killed.

This was actually implemented as part of MDEV-4506, parallel replication.
Unfortunately, one of the conditionals was reversed. So fsync of master.info
was disabled in non-gtid mode, instead of in gtid mode.

So fix the conditional to be correct.

inintentionally broken during merge 5.5->10.0-base

modified:
  mysql-test/r/mysql_tzinfo_to_sql_symlink.result

Always use the value of table::file->stats.records when checking
whether a table with HA_STATS_RECORDS_IS_EXACT flag contains not
more than 1 record.

The update of mysql.gtid_slave_pos during event replication used
the wrong way to disable binary logging for the table updates.
Fix to instead temporarily clear the OPT_BIN_LOG flag.

The bug was fixed by the patch applied to the 5.3 tree in the revision 3727.

sort directory data to make sure the same data order in the output
of mysql_tzinfo_to_sql on all platforms.

Add another column to SHOW SLAVE STATUS, and adjust test suite
to cope.

remove_eq_conds() in the function make_join_statistics().

Attempt to read the master-bin.state file always, even if the
binlog files (master-bin.index and master-bin.XXXXXX) have been
deleted.

This allows to easily preserve the binlog state when provisioning
a new server from a copy of an old one, without needing to copy
over the binlog files themselves.

mysql-test-run: *** ERROR: Could not find any of
/mariadb-5.5.34/sql/mysql_tzinfo_to_sql
/mariadb-5.5.34/build/client/mysql_tzinfo_to_sql
Fixed the directory list to search mysql_tzinfo_to_sql binary in.

The earlier pushed fix for the bug was incomplete. It did not remove
the main cause of the problem: the function remove_eq_conds()
removed always true multiple equalities from any conjunct, but did not
adjust the list of them stored in Item_cond_and::cond_equal.current_level.

Simplified the test case for the bug and moved it to another test file.

The fix triggered changes in EXPLAIN EXTENDED for some queries. 

MDEV-4725: Incorrect binlog state recovery if crash while writing event group

The binlog state was not recovered correctly if XA is not used (eg. InnoDB
disabled), or if server crashed in the middle of writing an event group to the
binlog.

With this patch, we ensure that recovery of binlog state is done even if we do
not do the full XA binlog recovery, and we ensure that we only recover fully
written event groups into the binlog state.

- Make log_slow_statement() always call delete_explain_query().

- Added testcase

Fixed.

- Don't pull out a table out of a semi-join if it is on the inner side of an outer join.
- Make join->sort_by_table= get_sort_by_table(...) call after const table detection 
  is done. That way, the value of join->sort_by_table will match the actual execution.
  Which will allow the code in setup_semijoin_dups_elimination() (search for 
  "Make sure that possible sorting of rows from the head table is not to be employed." 
  to see that "Using filesort" is going to be used together with Duplicate Elimination (
  and change it to Using temporary + Using filesort)

There were some places where insufficient locking between
parallel threads could cause invalid memory accesses and
possibly other grief.

This patch adds the missing locking, and moves the locking
into the struct rpl_binlog_state methods to make it easier
to see that proper locking is in place everywhere.

            -DINSTALL_SYSCONFDIR/-DDEFAULT_SYSCONFDIR specified

The reason for a bug is in support-files/CMakeLists.txt that tries to
install files in INSTALL_SYSCONF2DIR, without checking whether this
variable is actually defined. 

Normally INSTALL_SYSCONF2DIR is always defined if INSTALL_SYSCONFDIR is
defined, and support-files/CMakeLists.txt assumes that. But when one
specifies INSTALL_SYSCONFDIR manually on the command line, this
assumption might be broken.