Hide Minitest's aggregated results if outputting inline.

We'd see the failures and errors reported after the run, which is needless, when we've already
reported them.

Turns:

```

.......................................S....................F

This failed

bin/rails test test/models/bunny_test.rb:14

....

Finished in 0.100886s, 1020.9583 runs/s, 1001.1338 assertions/s.

  2) Failure:
BunnyTest#test_something_failing [/Users/kasperhansen/Documents/code/collection_caching_test/test/models/bunny_test.rb:15]:
This failed

103 runs, 101 assertions, 1 failures, 0 errors, 1 skips

You have skipped tests. Run with --verbose for details.
```

Into:

```

...................S.......................................F

This failed

bin/rails test test/models/bunny_test.rb:14

......................

Finished in 0.069910s, 1473.3225 runs/s, 1444.7143 assertions/s.

103 runs, 101 assertions, 1 failures, 0 errors, 1 skips
```

0 files changed, 0 insertions, 0 deletions