Summary:
As per javache comments in #8734.
Also removes now useless feature detection check.
**Test plan**
Tested that rIC still works in UIExplorer example.
Closes https://github.com/facebook/react-native/pull/8795
Differential Revision: D3572566
Pulled By: javache
fbshipit-source-id: 261d13d8b03898313f8b4184d634c70f81a61b62