panfrost: Blobber-db!

This series adds support for blobber-db, allowing us to capture shader-db stats from the blob for direct comparison of compiler quality. With this series and a modified test-shader-runner, the glmark2 shaders in upstream shader-db may be compiled with either and stats compared with normal upstream report.py.

Thank you to Rob Clark for his support throughout this process as the author of the original blobber-db for freedreno. His test-shader-runner is used here.