Create a CMake executable target (#49526)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/49526

Changelog: [Internal]

Introduce a binary tester for Fantom that will be used in runner when ready so OSS can run integration tests.

Here:
- Add BUCK target
- Add CMake target

Reviewed By: cortinico

Differential Revision: D69800975

fbshipit-source-id: 57e135e2a1cbfb88e0141ddc7859b9a29365ee1f