Tables in the table definition cache are keeping a cache buffer for blob
fields which can consume a lot of memory.
    
This patch introduces a maximum size threshold for these buffers.


sql/sql_base.cc:
  Added function free_field_buffers_larger_than to reclaim memory from blob
  field buffers too large to be cached.
sql/table.cc:
  Added function free_field_buffers_larger_than

BUG#37884: rpl_row_basic_2myisam and rpl_row_basic_3innodb fail sporadically in pushbuild
These have been fixed in 5.1-rpl. Re-applying fix for BUG#37884
in 5.1-bugteam, and disabling rpl_flushlog_loop for BUG#37733 in
5.1-bugteam.


mysql-test/extra/rpl_tests/rpl_row_basic.test:
  Missing sync_slave_with_master added.
mysql-test/suite/rpl/t/disabled.def:
  Disabling rpl_flushlog_loop until the fixed version gets
  merged from 5.1-rpl

sql/field.cc:
  Function is only used if replication is compiled in.

Deleted the removed tests.

No commit message

hhunger.

sql/log.cc:
  Auto merge

This does not fix the bug. It only disables the failing test.


mysql-test/suite/rpl/t/disabled.def:
  disable rpl_temporary

If the server failed to expired log files during start up it could crash.

sql/log.cc:
  Added predicate to protect againt cases when current_thd might be NULL.

use thread-local data structures in ha_release_temporary_latches()