matrix4x2 and matrix4x3 uniform arrays were broken because
the structure allocated to contain them was of the wrong
dimension, causing subsequent array elements to overwrite
a portion of the previous element.

Change-Id: I8129c7352f5470146994a0a89052a75fcfc4e54f
Reviewed-on: https://swiftshader-review.googlesource.com/4524Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>