Refine test of track
Refine test of track

This test made sure nothing broke, but didn't exercise the behavior I
want. A track's problems can include track-only ones, and track-only
problems exist.

ALso, checking implementations is not necessary for this test. The logic
in Implementations isn't changing.

exercism/trackler,exercism/trackler,Insti/trackler,Insti/trackler