Support layer: Support dumping output from KHR_pipeline_executable_properties #152

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.