Summary:
Closes https://github.com/facebook/react-native/pull/19910
Because of the way react-native local-cli communicates with metro, getWatchFolders function was always returning an empty array that triggered an error.
Reviewed By: hramos
Differential Revision: D8650733
fbshipit-source-id: 502ca469cdbfa04dab5127c1e330dc1d34fc02f8