Further nightlies cleanup (#53302)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53302

Those files can also go as they've been moved to
https://github.com/react-native-community/nightly-tests

Changelog:
[Internal] [Changed] -

Reviewed By: cipolleschi

Differential Revision: D80342950

fbshipit-source-id: 0b5cc8f424eefa00c48377fe2fbc2cca5e7ef48d