Metal: Adjust raster order groups AMD workaround condition Ensured that the raster order groups AMD workaround is used not only when there is no attachment on slot 0 but also when an existing attachment on slot 0 is disabled. Bug: angleproject:8263 Change-Id: I62352eb5d6fb1cce4b6a4723d41862c6c213b9d8 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5230638 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com> Reviewed-by: Kenneth Russell <kbr@chromium.org>