nir/schedule: return progress and fix metadata

Tracking if we changed the shader is somewhat complicated, so assume
we always do.

Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Konstantin Seurer <konstantin.seurer@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36291>
2 files changed