Add new failing test case: Inactive players shouldn't impede phase advance

The current implementation is waiting for all registered players to
have submitted answers before auto-advance (prior to a majority vote
to move on without anyone).

That seems like reasonable logic, except for a player that the server
has already noticed is no longer active (event stream connection has
dropped and server has indicated the player is gone from the game). We
don't want such an inactive player impeding the progress of the game.

This commit adds a test case capturing the behavior we actually want,
(so this test is currently failing).