Uniform blocks can be neither scalars not registers,
so make sure these never return true for uniform blocks.

Change-Id: Ib00afd175e4df92d45fe1aeaca865ea45fc13b0b
Reviewed-on: https://swiftshader-review.googlesource.com/4544Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>