translate: reserve more vertex-shader outputs

It's not just position that's special here, we also need space for other special vertex-shader outputs.

This fixes a crash with Zink on Lavapipe, because Zink always emits psize to avoid some shader-keys. While this might not be ideal, it's not illegal. So we need to handle it.

But it seems we're missing more, and this list is taken from compute_vertex_info() in lp_state_derived.c.