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.

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.

                  
Range scan in descending order for c <= <col> <= c type of
ranges was ignoring the DESC flag.
However some engines like InnoDB have the primary key parts 
as a suffix for every secondary key.
When such primary key suffix is used for ordering ignoring 
the DESC is not valid.
But we generally would like to do this because it's faster.
            
Fixed by performing only reverse scan if the primary key is used.
Removed some dead code in the process.

Deleted the removed tests.

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hhunger.

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

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

use thread-local data structures in ha_release_temporary_latches()