anv: Re-emit all compute state on pipeline switch

It's a very odd case to hit in the real world.  However, there are some
CTS tests which switch back and forth between dispatch and clear without
changing the pipeline.

Fixes: bc612536 "anv: Emit a dummy MEDIA_VFE_STATE before switching..."
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
(cherry picked from commit 0f60aa40)