Added avoid_dxt1_srgb_texture_format workaround

Bug: angleproject:4266
Change-Id: I286a9c66f6ea1d2c9d3587f6ca85608336eb44a6
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2033065Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>