[Reason] Better test formatting output/behavior.
[Reason] Better test formatting output/behavior.

Summary: The lines are more condensed now. Also, the tests will continue
to run after one fails. At the very end, if there was > 1 failure, it
will let you know to scroll up to inspect the failure - and that it
might be a preexisting failure.

Test Plan:

Reviewers:

CC:

facebook/reason,facebook/reason,let-def/reason,ak3n/reason,ak3n/reason,yunxing/reason,yunxing/reason,chenglou/reason,chenglou/reason,cristianoc/reason,ak3n/reason,let-def/reason,ak3n/reason,cristianoc/reason,let-def/reason,cristianoc/reason,chenglou/reason,facebook/reason,yunxing/reason,yunxing/reason