Use autogen for setting compressed format caps.

Bug: angleproject:2634
Change-Id: I8cfb57390751615c08f798f223f4db3deed2fff6
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2411979Reviewed-by: Le Hoang Quyen <le.hoang.q@gmail.com>
Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>