test: Exercise the situation coded for in the previous commit

Specifically, by changing bob's answer of "surfers" to "sand" he
should now receive one less point than before. That's because
"surfers" was worth one point (since only bob submitted it), but now
"sand" is worth 0. And _that's_ because bob is already getting full
credit of 3 points from "sands" for matching everybody, so he doesn't
deserve any additional credit for putting down an additional answer
that the group decided is equivalent to one he already has.