Remove the extra class hierarchy with classes TC_LOG_queued, TC_LOG_unordered,
and TC_LOG_group_commit, folding the code into the TC_LOG_MMAP and
TC_LOG_BINLOG classes. In particular TC_LOG_BINLOG is greatly simplified by
this, unifying the code path for transactional and non-transactional
commit.

Remove unnecessary locking of LOCK_log in MYSQL_BIN_LOG::write() (backport
of same fix from mysql-5.5).

Make TC_LOG_MMAP (and TC_LOG_DUMMY) derive directly from TC_LOG, avoiding the
inheritance hierarchy TC_LOG_queued->TC_LOG_unordered.

Put the wakeup facility for commit_ordered() calls into the THD class.

Some renaming to get better names.

Also add missing destroy of pthread_cond.

client/mysqltest.cc:
  Apply Serg's work-around for MySQL BUG#57491.
mysql-test/r/group_commit_binlog_pos.result:
  Accept different ways the server crash is detected.
mysql-test/t/group_commit_binlog_pos.test:
  Accept different ways the server crash is detected.
  Skip in row-based binlogging, as otherwise the binlog offsets will be different.

MWL#116: Efficient group commit: Fix assertion by moving init/deinit out of constructor in global static object.

MWL#116: Efficient group commit: Fix bug that binlog pos stored by XtraDB during commit was wrong when more than one commit in group.

Now the actual binlog position for each commit is stored in THD, and XtraDB
can fetch the correct value from within commit_ordered() or commit().


mysql-test/r/group_commit_binlog_pos.result:
  Test case for XtraDB binlog position.
mysql-test/t/group_commit_binlog_pos-master.opt:
  Test case for XtraDB binlog position.
mysql-test/t/group_commit_binlog_pos.test:
  Test case for XtraDB binlog position.
sql/log.cc:
  Save binlog position corresponding to commit in THD, and make accessible to storage engine.
sql/sql_parse.cc:
  Add generic crash point for use in test cases.
storage/xtradb/handler/ha_innodb.cc:
  Update to use new method of getting current binlog position that works with group commit.
storage/xtradb/handler/ha_innodb.h:
  Update to use new method of getting current binlog position that works with group commit.

Tweak the commit_ordered() semantics. Now it is only called for transactions
that go through 2-phase commit. This avoids forcing engines to make commits
visible before they are durable.

Also take LOCK_commit_ordered() around START TRANSACTION WITH CONSISTENT
SNAPSHOT, to get a truly consistent snapshot.

Preliminary commit for testing

Updated results for failing test cases (In all cases the estimated number of rows was different)

The condition over the outer tables now are extracted from
the on condition of any outer join. This condition is
saved in a special field of the JOIN_TAB structure for
the first inner table of the outer join. The condition
is checked before the first inner table is accessed. If 
it turns out to be false the table is not accessed at all
and a null complemented row is generated immediately.

the setting of optimizer switch for table elimination.

The implementation of the virtual method not_null_tables for the class
Item_outer_ref must always return 0.

Made sure that rr_quick is used to read the next record whenever
a quick select is used to retrieve the table records.

Fixed crashing bug when doing ALTER TABLE RENAME with transactional tables.

client/mysqltest.cc:
  Added errno to error message for system calls (delete, rename etc)
  Write error message for failures of system calls
mysql-test/include/cleanup_fake_relay_log.inc:
  Disable warnings for remove_file
mysql-test/include/diff_tables.inc:
  Disable warnings for remove_file
mysql-test/include/maria_empty_logs.inc:
  Disable warnings for remove_file
mysql-test/include/maria_make_snapshot.inc:
  Disable warnings for remove_file
mysql-test/include/maria_make_snapshot_for_feeding_recovery.inc:
  Disable warnings for remove_file
mysql-test/include/mysqlhotcopy.inc:
  Disable warnings for remove_file
mysql-test/include/ndb_backup.inc:
  Disable warnings for remove_file
mysql-test/include/ndb_backup_print.inc:
  Disable warnings for remove_file
mysql-test/r/alter_table_trans.result:
  Test of crashing ALTER TABLE RENAME bug
mysql-test/t/alter_table_trans.test:
  Test of crashing ALTER TABLE RENAME bug
mysql-test/t/mysqltest.test:
  Disable warnings for remove_file and move_file
mysys/my_copy.c:
  Fixed wrong error message
sql/sql_table.cc:
  Fixed crashing bug when doing ALTER TABLE RENAME with transactional tables.

libtool does not like it and fails the build.

- When reopening table during recovery, don't set file length from file sizes as file is not flushed.
New feature in Aria recovery:
- Create database directory if missing.



storage/maria/ma_recovery.c:
  Don't print Query: twice when running maria_read_log
  Create database directory if missing. (Needed when running maria_read_log on an empty database direcory during testing)
  More DBUG_print
  Fixed bug: When reopening table during recovery, don't set file length from file sizes as file is not flushed.

The problem could be demonstrated with an outer join of two single-row
tables where the values of the join attributes were null. Any query
with such a join could return a wrong result set if the where
condition of the query was not empty. For queries with empty
where conditions the result sets were correct.
This was the consequence of two bugs in the code:
 - Item_equal objects for on conditions of outer joins were
   not built if the processed query had no where condition
 - the check for null values in the code that evaluated constant 
   Item_equal objects was incorrect.
Fixed both above problems.
Added a test case for the bug and adjusted results for some other
test cases.