* Update arc config for ArcanistBaseUnitTestEngine -> ArcanistUnitTestEngine
Test Plan: Execute Java test suite
Reviewers: yhchiang
Differential Revision: https://reviews.facebook.net/D61911
* Fix for arc use of base64 command on Max OS X
Test Plan: Run on `arc diff` on Mac OS X and Linux
Reviewers: yhchiang
Differential Revision: https://reviews.facebook.net/D61917
