Confirm that tabulator works properly if we end up with two candidates who are tied

[tarheel]

I mentioned this in #646: I'm not sure we actually handle this situation correctly. It should trigger a tie-break and then, rather than eliminating the loser, simply stop and declare the winner. But I don't think that's what it will do right now.

[tarheel]

(Note: I believe this is only a problem for single-winner contests. I think we handle ties at the end properly for multi-winner contests. But not 100% sure about that either.)