freedreno/ir3/ra: be better at failing

It doesn't happen much.  But it's annoying when we hit an impossible
condition deep in RA 90% thru a long test run.  Add some ra_assert()/
ra_unreachable() helper macros so we can bail cleanly and fail RA.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5907>
2 files changed