Vulkan: Optimize glFramebufferSubInvalidate If glFramebufferSubInvalidate() is called with an area that covers the whole framebuffer, behave as if glFramebufferInvalidate() is called. This allows deferred clears to be removed for example, and attachment contents to be marked undefined. Bug: angleproject:4988 Change-Id: Iff3f291ea6c07abccc2740174d0451b432ac5da8 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2508977 Reviewed-by: Charlie Lao <cclao@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>