Bug #48370  Absolutely wrong calculations with GROUP BY and
  decimal fields when using IF

Added the test cases in the above two bugs for regression
testing.
Added additional tests that demonstrate a incomplete fix.
Added a new factory method for Field_new_decimal to 
create a field from an (decimal returning) Item.
In the new method made sure that all the precision and 
length variables are capped in a proper way. 
This is required because Item's can have larger precision
than the decimal fields and thus need to be capped when
creating a field based on an Item type.
Fixed the wrong typecast to Item_decimal.

Testing for presence of stuff in a hash inside the function
that's filling in the hash creates chicken-and-egg type of problems.
This results in test suite failures in mysql-pe in debug mode and 
adds bad initialization dependency in 5.1.
Fixed by removing the debug code.

In RBR, All statements operating on temporary tables should not be binlogged.
Despite this fact, after executing 'TRUNCATE... ' on a temporary table, 
the command is still logged, even if in row-based mode. Consequently, this raises
problems in the slave as the table may not exist, resulting in an
execution failure. Ultimately, this causes the slave to report
an error and abort.

After this patch, 'TRUNCATE ...' statement on a temporary table will not be
binlogged in RBR.

The problem is that the server could crash when attempting
to access a non-conformant proc system table. One such case
was a crash when invoking stored procedure related statements
on a 5.1 server with a proc system table in the 5.0 format.

The solution is to validate the proc system table format
before attempts to access it are made. If the table is not
in the format that the server expects, a message is written
to the error log and the statement that caused the table to
be accessed fails.

Not all my_hash_insert() calls are checked for return value.

This patch adds appropriate checks and failure responses
where needed.

This patch introduce a limit on the time the query cache can
block with a lock on SELECTs.

Other operations which causes a change in the table
data will still be blocked.

implement Davi's review suggestions (post-push fixes)

Fixed crash caused by x64 int/long incompatibility introduced
in Bug #29125.

When merging ranges during calculation of the result of OR
to two range sets the current range may be obsoleted by the 
resulting merged range.
The first overlapping range can be obsoleted as well.

Fixed by moving the pointer to the first overlapping range to the
pointer of the resulting union range.
Added few comments at key places in key_or().

Fixed 2 errors in comp_err executable : 
1. Wrong (off by 1) length passed to my_checksum()
2. strmov() was used on overlapping strings. This is
 not legal according to the docs in stpcpy(). Used 
the overlap safe memmove() instead.

Problem: Some system functions that could return different values on
master and slave were not marked unsafe. In particular:
 GET_LOCK
 IS_FREE_LOCK
 IS_USED_LOCK
 MASTER_POS_WAIT
 RELEASE_LOCK
 SLEEP
 SYSDATE
 VERSION
Fix: Mark these functions unsafe.

Fixed a problem with the test case when executed with ps-protocol.
There the conflicing lock would be noticed during prepare, not
during execution of the insert - leading to a different (but 
equally appropriate) error message.

           DELETE IGNORE

The ER_CANT_UPDATE_USED_TABLE_IN_SF_OR_TRG error was set in the
diagnostics area when it happened, but the DELETE cleanup code
never checked for a non-fatal error condition, thus trying to
set diag.area to "ok".  This triggered an assert checking that
the diag.area was empty.

The fix was to test if there existed a non-fatal error condition
(thd->is_error() before ok'ing the operation.

The problem was a "self-deadlock" if the connection issuing INSERT DELAYED
had both the global read lock (FLUSH TABLES WITH READ LOCK) and LOCK TABLES
mode active. The table being inserted into had to be different from the 
table(s) locked by LOCK TABLES.

For INSERT DELAYED, the connection thread waits until the handler thread has
opened and locked its table before returning. But since the global read lock
was active, the handler thread would be unable to lock and would wait for the
global read lock to go away.

So the handler thread would be waiting for the connection thread to release
the global read lock while the connection thread was waiting for the handler
thread to lock the table. This gave a "self-deadlock" (same connection,
different threads).

The deadlock would only happen if we also had LOCK TABLES mode since the
INSERT otherwise will try to get protection against global read lock before
starting the handler thread. It will then notice that the global read lock
is owned by the same connection and report ER_CANT_UPDATE_WITH_READLOCK.

This patch removes the deadlock by reporting ER_CANT_UPDATE_WITH_READLOCK
also if we are inside LOCK TABLES mode.

Test case added to delayed.test.