- The depth/stencil related tests are now disabled since I found out
that the tests are too simple to find issues if there is a flip since
they use only a single color and no gradient / checked board.
This is left to implement in the Vulkan backend later on.

Bug: angleproject:2673
Change-Id: I8f7091d4b9c8c3bec0353ebab28304b6209ea350
Reviewed-on: https://chromium-review.googlesource.com/1129629Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Luc Ferron <lucferron@chromium.org>