This speeds up our draw call benchmark.

BUG=angleproject:959

Change-Id: I9a916a6c344493cc96873ae5f4ec337c181dc487
Reviewed-on: https://chromium-review.googlesource.com/266026Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>