Prefer Minitest's location for test failures.

When running tests, the Rails test runner would report the start of the test method as the test failure.

For this test:

```ruby
1 require 'test_helper
2
3 class BunnyTest < ActiveSupport::TestCase
4   test "something failing" do
5     assert false, 'This failed'
6   end
7 end
```

The runner outputs 5 instead of 4:

```
............................................F

This failed

bin/rails test test/models/bunny_test.rb:5

........
```

0 files changed, 0 insertions, 0 deletions