Mostly inlining checks on the hot draw call path.
Slight increase in draw call validation performance. (Up to 13%)

Bug: angleproject:2747
Change-Id: I34c4d7f412c3bca5e559e9bfb5689c0618bb7536
Reviewed-on: https://chromium-review.googlesource.com/1171506Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>