No-op incomplete framebuffer invalidation. It's always legal in GL to no-op framebuffer invalidation. When the FBO is incomplete we can't pull RTs safely so no-oping incomplete invalidate calls saves us from fuzzer bugs and crashes. Bug: angleproject:3971 Change-Id: Ide550a22e6c17a28e5042165831dd684567d81fe Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2227038 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>