The specialization constant crrev.com:/c/2514773 was hitting test
failures on pixel2 devices but not able to reproduce on pixel4. Now I
think the problem is likely attribute to QC driver bug
http://b/173636783. And we have disabled specialization constant code
path on older driver. This CL is to re-enable those tests that we
skipped in that CL so that they gets tested.

Bug: b/173636783
Change-Id: I3452abee26ebc6b8e81e68831fb2c698e464cf07
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2555858
Commit-Queue: Tim Van Patten <timvp@google.com>
Reviewed-by: Tim Van Patten <timvp@google.com>