Vulkan: Rotate gl_FragCoord for Android pre-rotation This extends the current y-flip that's done for gl_FragCoord. Now, gl_FragCoord is rotated and then flips both the x and y-axis. Bug: angleproject:4643 Bug: b/156395519 Change-Id: Iada8680eda8322f7382ff242e4a9422a66114f05 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2210936 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Ian Elliott <ianelliott@google.com>