Metal: use release-consume order for queue's serials. Currently mtl::CommandQueue's mCommittedBufferSerial, mCompletedBufferSerial use relaxed memory order for load & store. They should use consume & release memory order respectively instead. Bug: angleproject:8406 Change-Id: I871259f1a6cca0e63d6c24b7592e7b80fd443dff Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5015524 Reviewed-by: Kenneth Russell <kbr@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Quyen Le <lehoangquyen@chromium.org>