Fix fuzzy color check in ClearTest. This test was failing on some systems because of overly stringent color expectations. BUG=angle:809 Change-Id: I817de315ff6de46fb87f8ed1c21e3bb62c133176 Reviewed-on: https://chromium-review.googlesource.com/225262 Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Shannon Woods <shannonwoods@chromium.org>