Make sure all extension strings start with GL_
Make sure all extension strings start with GL_

BUG=angleproject:3974

Change-Id: I01bb5e6f7dec800ac36464a7d64c26998a0b087f
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1845473
Commit-Queue: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle