Clear uncleared textures as a dirty object. This removes the check for robust resource init from prepareForDraw. It should improve performance more when WebGL compatiblity is enabled. Also inlines Context::syncDirtyBits and Context::prepareForDraw. Reduces CPU overhead in all draw and dispatch calls up to 5%. Bug: angleproject:2966 Change-Id: I7e9009a501c0331a6140bc78678aef27e38c3df2 Reviewed-on: https://chromium-review.googlesource.com/c/1347453 Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>