BREAKS RBR

Analysis:
--------
A table created using a query of the format:
CREATE TABLE t1 AS SELECT REPEAT('A',1000) DIV 1 AS a;
breaks the Row Based Replication.

The query above creates a table having a field of datatype
'bigint' with a display width of 3000 which is beyond the
maximum acceptable value of 255.

In the RBR mode, CREATE TABLE SELECT statement is
replicated as a combination of CREATE TABLE statement
equivalent to one the returned by SHOW CREATE TABLE and
row events for rows inserted. When this CREATE TABLE event
is executed on the slave, an error is reported:
Display width out of range for column 'a' (max = 255)

The following is the output of 'SHOW CREATE TABLE t1':
CREATE TABLE t1(`a` bigint(3000) DEFAULT NULL)
                  ENGINE=InnoDB DEFAULT CHARSET=latin1;

The problem is due to the combination of two facts:

1) The above CREATE TABLE SELECT statement uses the display
   width of the result of DIV operation as the display width
   of the column created without validating the width for out
   of bound condition.
2) The DIV operation incorrectly returns the length of its first
   argument as the display width of its result; thus allowing
   creation of a table with an incorrect display width of 3000
   for the field.

Fix:
----
This fix changes the DIV operation implementation to correctly
evaluate the display width of its result. We check if DIV's
results estimated width crosses maximum width for integer
value (21) and if yes set it to this maximum value.

This patch also fixes fixes maximum display width evaluation
for DIV function when its first argument is in UCS2.