ac/nir: Don't count vertices and primitives in wave after culling.

ac/nir: Don't count vertices and primitives in wave after culling.

These are not needed anymore, because the EXEC mask doesn't depend on them.

Fossil DB results on Sienna Cichlid (with NGGC on):

Totals from 58239 (45.27% of 128647) affected shaders:
Latency: 138113669 -> 138285372 (+0.12%)
InvThroughput: 22404840 -> 22405245 (+0.00%)

No Fossil DB changes with NGGC off.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11908>