Migrate mounting tests to Fantom (#49018)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/49018

Changelog: [internal]

Migrates the mounting layer logs from C++ (640 lines of code) to Fantom (248 lines!!!).

This is 1:1 translation of the test.

Reviewed By: javache

Differential Revision: D67549200

fbshipit-source-id: 735fa3203cd04dd5b3b4b5174e0c96fdc2354993