I noticed that when a player is reactivated, (that is, by starting a
new event stream by means of a cookie associated with a pre-existing
cookie for a player that had been deactivated), the server was not
properly activating the player.
This commit adds a new failing test case that demonstrates the bug. We
reactivate dale for a 4-player game, but then the server advances the
game out of the answering phase when only 3 players have submitted an
answer. This demonstrates that dale isn't being considered active.