dlist: use a new OPCODE to avoid loading cold data

dlist: use a new OPCODE to avoid loading cold data

Also add a 'bool copy_to_current' param to vbo_save_playback_vertex_list:
this way we can decide if we need to call playback_copy_to_current without
loading any cold data.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11493>