Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/39780
This diff removes flags and setups from the files to turn on and off the new architecture. The script is meant to run only on pre-alpha builds.
## Changelog:
[Internal] - Add script to remove prealpha flags
Reviewed By: cortinico
Differential Revision: D49376471
fbshipit-source-id: 754bf6f9d5b94da77111798200bbaaa3347fb678
Riccardo Cipolleschi