Vulkan: Fix sub invalidate marking render targets undefined When glInvalidateSubFramebuffer is called, the framebuffer is only partially invalidated. FramebufferVk::invalidateImpl was nevertheless marking the render targets as undefined, which would lead the subsequent render pass have loadOp=DONT_CARE. This is not correct, as the rest of the framebuffer is expected to still be valid. Bug: angleproject:4859 Change-Id: I2e64baa32b1fc84beb8008411b564cd7619af962 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2309111 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com>