When clearing to zeros or ones on some Intel drivers on Mac, the clear color
would be incorrect.

This replicates the chromium clear_to_zero_or_one_broken workaround.

BUG=angleproject:3672

Change-Id: I0f065420b577bd8f8d931ccdbeeebdcbf9fd08d2
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1692977
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>