Uniform buffer uniform unpacking utility function

Uniform buffer uniform unpacking utility function

When data is packed into uniform blocks, some data isn't formatted in
a way that fits how data is usually represented, which is the case
for booleans and row major matrices. In these 2 cases, the variables
are unpacked into temporaries before being used. Booleans can be any
integer value and any non-zero value represents "true", so the value
in the uniform buffer has to go through an int to bool conversion
before being used. For row major matrices, a given register of that
matrix has to be transposed into a temporary before being used.

Change-Id: I0e001ceff2ce9be9a3570171e184586afc48c02d
Reviewed-on: https://swiftshader-review.googlesource.com/5040
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>