This improves performance of all draw call validation. The error that
should be generated on the draw call is cached in the Context. The
cache is updated in several places.

Bug: angleproject:2747
Change-Id: I178617623731608e2e7166b53ab6489d8b742ff5
Reviewed-on: https://chromium-review.googlesource.com/1158612Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Frank Henigman <fjhenigman@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>