Add failing test case for a major match-voting bug

Specifically, the majority requirement for a word match to be
considered succesful has been counting all registered players rather
than only the players actually in the current game.

In the degenerate case, having more inactive registered players than
active would mean that no matches would ever be judged as valid even
with unanimous voting. Obviously, this is a disastrous bug.

The test case added here currently fails, (where one person voting
should be considered a (non-strict) majority in a 2-person game).