Update the build constraints so that OpenGL is used both on macOS AMD64 and ARM64, while OpenGL ES is used on iOS. This fixes the build on M1 Macs. For golang/go#43237. Change-Id: Iad2d406eaf0ddbe72f221f497dd074ad0b22015e Reviewed-on: https://go-review.googlesource.com/c/mobile/+/278779 Trust: Dmitri Shuralyov <dmitshur@golang.org> Reviewed-by: Hajime Hoshi <hajimehoshi@gmail.com>