anv: Decouple primitive replication check from the fragment shader

anv: Decouple primitive replication check from the fragment shader

Now that we're using nir_intrinsic_load_layer_id for ViewIndex, we can
use primitive replication even when the FS uses ViewIndex.  Also, only
check that active_stages doesn't contain anything other than VS and FS,
not that it's exactly VS | FS.  This both decouples things more and
allows primitive rplication in the depth-only case where we have no
fragment shader at all.

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17602>