Metal: Wraparound int arithmetic for add, sub Implement wraparound int arithmetic for int, ivec +, -, +=, -=, ++, --. All of the added tests pass also without the changes. Bug: angleproject:382215759 Change-Id: I7605582ab2931e63010c34fba474797f7edd19f9 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6578729 Auto-Submit: Kimmo Kinnunen <kkinnunen@apple.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Kimmo Kinnunen <kkinnunen@apple.com>