Metal: Flush with NoWait on iOS when hitting renderpass count limits Avoid deviating between iOS and macOS in this regard. The behavior should be the same for the caller as well as the implementation. Bug: chromium:1466696 Bug: angleproject:363984104 Change-Id: I39160bcc0a54ea9c767e1109d80cb4d71ecdf207 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5830799 Auto-Submit: Kimmo Kinnunen <kkinnunen@apple.com> Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>