This test has a bug where the masked clear flag is not being set
properly, leading to incorrect test behaviour and missing coverage.

Until this bug is fixed in dEQP we can override it with a fixed
version.

Also remove a prior override that had an upstreamed fix.

Bug: angleproject:2455
Change-Id: Ia2c57251b2a97eb5b4d8a4bdb0ce31796a66ea01
Reviewed-on: https://chromium-review.googlesource.com/1013859Reviewed-by: Frank Henigman <fjhenigman@chromium.org>
Reviewed-by: Luc Ferron <lucferron@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>