Support layer: Support dumping output from KHR_pipeline_executable_properties

[solidpixel]

Mali drivers will now support returning compiler statistics for compiled pipelines via the new KHR_pipeline_executable_properties extension, so we should support dumping that information somehow.

One proposal is to add a new shader manipulation layer (which can in future be used for edit/replay) and so we should just match fossilize and output this in addition to the other data that fossilize outputs.

TODO: Need to work out how to report these.

[solidpixel]

Formatting:

Baseline proposal: One file per shader, and support both plain text and json format.
Alternative option: One CSV shows details of all created shaders.

Shader identification:

• SHA1 of shader code
• SHA1 of shader code + PSO state
• Shader object debug name
• First use container debug name (e.g. render pass name)