Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/34100
This Diff continue the effort of refactor and test the cocoapods script, moving hermes setup in a dedicated `hermes.rb` file and adding some tests on the logic of the hermes handling.
## Changelog
[iOS][Changed] - move and test Hermes setup from react_native_pods script into a dedicated file
Reviewed By: cortinico
Differential Revision: D37522432
fbshipit-source-id: 91112476aac576a30110e5dcd4e46fa12241962a