Forcing draw for clear only appears to be needed on Pixel 2.

Test: angle_perftest --gtest_filter="*free_fire*"
Bug: angleproject:4836
Change-Id: I4446adc04a8e5cf7b0bfef68ec70122e847755a6
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2495484Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>