Add pixels checks to bandingTest on Android +toggle GL_DITHER Bug: b/284462263 Change-Id: I69122d1d53d03a2e75d498e77a669099a568ab3c Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4628974 Commit-Queue: Roman Lavrov <romanl@google.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>