Vulkan: Work around unused sampler validation. Work around glslang's improved validation by using a valid but very high layout binding. This should be more robust. Tests already passing: dEQP-GLES2.functional.state_query.shader.uniform_value_sampler Bug: angleproject:2691 Bug: angleproject:2612 Bug: angleproject:2600 Change-Id: Ie78ae89f76cc0a42806724b622d7f201241bd041 Reviewed-on: https://chromium-review.googlesource.com/1117477 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>