Add RAII helpers for GL tests. These methods can obviate the need for glGen/Delete calls in tests. BUG=angleproject:1407 Change-Id: Ied571e48db92bd1d4f4089d91a95e7c7fafcfcaf Reviewed-on: https://chromium-review.googlesource.com/350904 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>