The new dEQP takes advantage of the EXT entry point. If it is
missing, dEQP will trigger an unexpected crash.

Bug: angleproject:2319
Change-Id: Ib9a32931cd50bc96d9918662f16262772afbe36a
Reviewed-on: https://chromium-review.googlesource.com/889695Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>