Metal: Support non-layered 2D array shader images Fixed: angleproject:8125 Change-Id: Id148c09d948487bb677c4a3af746e6ea151d84a7 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5604225 Reviewed-by: Quyen Le <lehoangquyen@chromium.org> Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com>