The fix is in 2 parts:
1) Multiplying a matrix by a float was failing due to attempting
to use the matrix's index on the float, thus going out of bounds.
2) Multiplying a vector or matrix by vectors or matrices of a
different size was not causing a failure, but now it does.

BUG=18450319

Change-Id: Ie01a77eb32d7d52fcd0a803f3e5efc24c625dbfd
Reviewed-on: https://swiftshader-review.googlesource.com/1450Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>