Use unused uniform blocks workarounds on Linux AMD. The Linux AMD driver optimizes out uniform blocks where WebGL2 and maybe OpenGL ES 3 forbids it. Try to fix this by enabling the workaround that was made for the same problem on OSX. BUG= Change-Id: If3b18ec1f463582d7594221a6f2a08d25207e737 Reviewed-on: https://chromium-review.googlesource.com/506189 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org>