Vulkan: Add support for GL_EXT_fragment_shading_rate_primitive Add support for built-in GL_EXT_fragment_shading_rate_primitive and tests. Bug: angleproject:397255625 Change-Id: I0f37a87a73e869a91e39402f01e53166b359ec3c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6850353 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Auto-Submit: Panfeng Hou <panfeng.hou@arm.com> Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com> Reviewed-by: Charlie Lao <cclao@google.com> Commit-Queue: Amirali Abdolrashidi <abdolrashidi@google.com>