Vulkan: Rearrange graphics pipeline desc bits In preparation for use of VK_EXT_graphics_pipeline_library, the pipeline state is split in three contiguous regions: - Vertex input - Pre-rasterization and fragment stages ("Shaders" for short) - Fragment output There is some state that affects both Shaders and Fragment output, which is split and placed in between the two. This will allow the hash and compare functions to eventually access each of those pipeline subsets as a contiguous piece of memory. Bug: angleproject:7369 Change-Id: Iedc4cf15ed6c7fed6ba93039889fbf5dd191e041 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3949914 Reviewed-by: Yuxin Hu <yuxinhu@google.com> Reviewed-by: Charlie Lao <cclao@google.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>