Prevent double rendering of unit test results
Summary: D14037 had the logic slightly wrong and unit test results are now being double rendered.
Test Plan: Ran a unit test with arc unit -- path/to/test and saw the results rendered only once.
Reviewers: Blessed Reviewers, epriestley
Reviewed By: Blessed Reviewers, epriestley
Subscribers: Korvin
Differential Revision: https://secure.phabricator.com/D14495