Summary: Currently, some YogaKit tests fail when they are run in Xcode, but pass in BUCK. This cleans up the tests so that they more definitively test what they say they are testing, and the results are not affected by the enviroment they are run in.
Reviewed By: emilsjolander
Differential Revision: D4453745
fbshipit-source-id: 238e41960afe63d31e9f6efdcd947cfac39f2dc4