This also places textureSize(gsampler2DMS) correctly in the ESSL 3.10
builtins instead of ESSL 3.00 builtins.

BUG=angleproject:2775
TEST=angle_unittests

Change-Id: Ieb0f7a7424a5558a5569af6d4fcbcc9b12ec9840
Reviewed-on: https://chromium-review.googlesource.com/1186466
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>