GL: Use glClear for robust init on Android. The allowClearForRobustResourceInit was used to work around driver bugs on other Windows and Linux and has a lot of CPU overhead. Re-enable it on Android (except some older Adreno). Bug: chromium:983167 Change-Id: Ibfb4eb4fcdc7310fb6181c57f5c8d7a645ffad9d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3011420 Reviewed-by: Peng Huang <penghuang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>