backporting a part of the bug patch to 5.1.29 tree which uses an older version of mtr.

Bug#37536: Thread scheduling causes performance degradation at low thread count

Deprecated --skip-thread-priority startup option as newer versions of
the server won't change the thread priorities by default.

Giving threads different priorities might yield marginal improvements
in some platforms (where it actually works) but on the other hand it
might cause significant degradation depending on the thread count and
number of processors. Meddling with the thread priorities is a not a
safe bet as it is very dependent on the behavior of the cpu scheduler
and system where MySQL is being run.

From MySQL 6.0 and up the default behavior is that of not modifying
the threads priorities.

Repush of change to fix tests on Pushbuild.

Link with mtmalloc on Solaris as it is done in our release builds.
Replace deprecated flag with the newer option as already done in
other scripts.

Post-merge bug fix: lock_type is a enumeration type and not a bit mask.

Server created "arc" directories inside database directories and
maintained there useless copies of .frm files.

Creation and renaming procedures of those copies as well as
creation of "arc" directories has been discontinued.
Removal procedure has been kept untouched to be able to
cleanup existent database directories by the DROP DATABASE
query. Also view renaming procedure has been updated to remove
these directories.

     JOIN for the subselect wasn't cleaned if we came upon an error
     during sub_select() execution. That leads to the assertion failure
     in close_thread_tables()

     part of the 6.0 code backported

per-file comments:
  mysql-test/r/sp-error.result
Bug#37949 Crash if argument to SP is a subquery that returns more than one row 
    test result

  mysql-test/t/sp-error.test
Bug#37949 Crash if argument to SP is a subquery that returns more than one row 
    test case

  sql/sp_head.cc
Bug#37949 Crash if argument to SP is a subquery that returns more than one row 
    lex->unit.cleanup() call added if not substatement

The problem is that when statement-based replication was enabled,
statements such as INSERT INTO .. SELECT FROM .. and CREATE TABLE
.. SELECT FROM need to grab a read lock on the source table that
does not permit concurrent inserts, which would in turn be denied
if the source table is a log table because log tables can't be
locked exclusively.

The solution is to not take such a lock when the source table is
a log table as it is unsafe to replicate log tables under statement
based replication. Furthermore, the read lock that does not permits
concurrent inserts is now only taken if statement-based replication
is enabled and if the source table is not a log table.

      
In order to improve the performance when replicating to partitioned
myisam tables with row-based format, the number of rows of current 
rows log event is estimated and used to setup storage engine for bulk
inserts.

Bug#38311 - Fix of some cruft from remove_files in ndb_autodiscover.test, clean up of distinct.test,
and replacing error numbers with error names.

Trimmed some error-prone and variable portions of the test and added 'flush status' to ensure deterministic test

            
A stored procedure involving substrings could crash the server on certain
platforms because of invalid memory reads.
          
During storing the new blob-field value, the cached value's address range
overlapped that of the new field value. This caused problems when the 
cached value storage was reallocated to provide access for a new 
characater set representation. The patch checks the address ranges, and if
they overlap, the new field value is copied to a new storage before it is
converted to the new character set.