Just like invalidate, this should attempt to sync the framebuffer after
nooping incomplete framebuffers.

Bug: chromium:1119669
Change-Id: Ie4bc6211bbeb1765674f7e0aef884faf7ceb8cc7
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2375565Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>