Also added a test to validate we can change the filter mode between
two draws successfully.

Bug: angleproject:2478

Change-Id: I80730cdafc6bbdbf61839c6c8eb98d85f7423d92
Reviewed-on: https://chromium-review.googlesource.com/1020084
Commit-Queue: Luc Ferron <lucferron@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>