Summary:
This diff forces ReactEventEmitter to use RCTEventEmitter as default event emitter class. This is necessary because of T54134149.
This is a temporary fix until we find the root cause of T54134149
Reviewed By: JoshuaGross
Differential Revision: D17422611
fbshipit-source-id: 159b216434c79466427b7b1a2b0f71f466b0f606