Summary:
This diff does two things
- Clean up some of the generated code making the files smaller.
- Add experiment support to generated tests allowing us to use gentest for things still being experimented with such as more compliant flex-basis behavior.
Reviewed By: gkassabli
Differential Revision: D4226734
fbshipit-source-id: 2cc1471c21883e8e326f16e7a8bb1a3657acd84b