Vulkan: Fix for framebuffer blit and Y flip - 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/1129629 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Luc Ferron <lucferron@chromium.org>