Vulkan: Implement depth_range dirty bit and enable tests - Additional fix in GlslWrapper.cpp to remove the @@ markers for unused attributes. - Enables 28 dEQP gles2 tests in functional.depth_range.* Bug: angleproject:2454 Change-Id: I1a6f72d846b476ba681140d4b242208d24e18b95 Reviewed-on: https://chromium-review.googlesource.com/1014262 Commit-Queue: Luc Ferron <lucferron@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org>