Post-push fix.
Problem: After the original bugfix, if a statement is unsafe,
binlog_format=mixed, and engine is statement-only, a warning was
generated and the statement executed. However, it is a fundamental
principle of binlogging that binlog_format=mixed should guarantee
correct logging, no compromise. So correct behavior is to generate
an error and don't execute the statement.
Fix: Generate error instead of warning.
Since issue_unsafe_warnings can only generate one error message,
this allows us to simplify the code a bit too:
decide_logging_format does not have to save the error code for
issue_unsafe_warnings

Also renamed current_stmt_binlog_row_based to
current_stmt_binlog_format_row for consistency

with the newer pb2 testing environments

This fixes the regression introduced in 5.1 that prevents 64 bit builds on Intel while still keeping the core2 hack operational so the cluster can build.

Remove a self assignment.
Rework a few constructs to avoid a potential overflow.

Based upon patch contributed by Michal Hrusecky

On 64-bits machines the calculation gets the wrong types and results
in very large numbers. Fixed by explicitly cast month to (int)

Failing to connect would release parts of the MYSQL struct.
We would then proceed to try again to connect without re-
initializing the struct.

We prevent the unwanted freeing of data we'll still need now.

Update the test case for BUG#44331 to fix the push build failure.

            results in server crash 
 
check_group_min_max_predicates() assumed the input condition 
item to be one of COND_ITEM, SUBSELECT_ITEM, or FUNC_ITEM. 
Since a condition of the form "field" is also a valid condition 
equivalent to "field <> 0", using such a condition in a query 
where the loose index scan was chosen resulted in a debug 
assertion failure. 
 
Fixed by handling conditions of the FIELD_ITEM type in 
check_group_min_max_predicates(). 

If an EVENT is created without the DEFINER clause set explicitly or with it set  
to CURRENT_USER, the master and slaves become inconsistent. This issue stems from 
the fact that in both cases, the DEFINER is set to the CURRENT_USER of the current 
thread. On the master, the CURRENT_USER is the mysqld's user, while on the slave,  
the CURRENT_USER is empty for the SQL Thread which is responsible for executing 
the statement.

To fix the problem, we do what follows. If the definer is not set explicitly,  
a DEFINER clause is added when writing the query into binlog; if 'CURRENT_USER' is 
used as the DEFINER, it is replaced with the value of the current user before 
writing to binlog.