Use a table for vertex attrib type validation. No clearly sampled effect on performance but should require fewer instructions. May lead to future improvements. Bug: angleproject:3014 Change-Id: I64e155926ae2c553b059265780e72e91f91f097c Reviewed-on: https://chromium-review.googlesource.com/c/1393906 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Yuly Novikov <ynovikov@chromium.org>