Related tests pass, modulo the current masking issue.

Change-Id: Iac1103e74a9cf18c480289210dd2bd957cc41069
Reviewed-on: https://swiftshader-review.googlesource.com/5300Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>