WIP: anv: Expose pipeline setup commands through VK_KHR_pipeline_executable_properties

This MR adds support to expose a decoded version of the batch snippet stored in the VkPipeline through VK_KHR_pipeline_executable_properties so that you can see it in RenderDoc. Seemed like it might be useful to someone. It's far from perfect as it doesn't decode any shaders or dynamic state due to a lack of STATE_BASE_ADDRESS.

There are also a couple fixes in here so I'd like at least those reviewed.