Hangs and assertions with validate.test.playbin3.intensive_state_change_selecting_stream
The biggest issue is ending up "reconfiguring" output slots which don't yet have the active stream yet (it's pending, traversing the multiqueue but hasn't come out yet).
This causes a bunch of assertions.
It would seem as thought the stream switching code doesn't 100% handle the case where the various streams are traversing the multiqueue. See code in handle_stream_switch()
and where we add a idle_reconfigure()
on slots which don't yet have an active stream.