Rename setUpDefaultReactNativeEnvironment to scope it better (#53267)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53267

Changelog: [internal]

Test files that verify the behavior of the global setup can only have a single test, as we can't really reset it across tests. Because of that, I'm renaming the current one to make the behavior under test more explicit.

Reviewed By: rshest

Differential Revision: D80177333

fbshipit-source-id: df9eeba15906bc6071940824dad9e576a267f499