Summary:
Makes sure that the global (standard) `performance` instance is initialized to still both provide `Performance.now()` as before, but also allows for the newly implemented functionality from the WebPerf API, such as marks/measures.
Changelog: [Internal]
Reviewed By: christophpurrer
Differential Revision: D42017812
fbshipit-source-id: ddbe79e91b45a84871de94018305f2a4536ada4b