Metal: Override internal format of images Add support for overriding the internal format when binding Metal textures to EGL images. Fixed: angleproject:8552 Change-Id: I364a88a2e608e462c5216c92927679814ab91ca5 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5310305 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Kenneth Russell <kbr@chromium.org>