OF TOTAL REDO LOG SIZE

Problem:

The patch rb#5399 for Bug #16963396 INNODB: USE OF LARGE EXTERNALLY-STORED
FIELDS MAKES CRASH RECOVERY LOSE DATA limits the size of the total blob per
row to be less than or equal to 10% of the redo log file size.  But this is
too strict.  The total blob length per row can be upto 10% of the total
redo log size.

Solution:

Relax the restriction and allow the blob length per row to be 10% of the total
redo log size.  Also added a test case to demonstrate that the blob length
per row can be greater than one single redo log file size, and that its
limitation is only w.r.t the total redo log size.

rb#6672 approved by Marko and Jorge.