nir,agx: optimize uniform atomics
This series enables opt_uniform_atomics for AGX. This contains:
- a few agx bug fixes
- divergence analysis for AGX intrinsics
- knob for uniform atomics to work in lowered AGX fragment shaders
- agx-specific intrinsic wired up for uniform subgroup optimizations to clean up the resulting code
Cc @daniel-schuermann @idr as likely reviewers
Edited by Alyssa Rosenzweig