This does shader analysis that is more niche than regular shader info.
It's planned to be used by nir_restructure_tcs_flow as discussed here:
https://gitlab.freedesktop.org/mesa/mesa/-/issues/11910
It's also useful for driver-specific passes.
The code for gathering "all_invocations_define_tess_levels" is copied
from radeonsi. The rest is new.
Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31447>
