Summary:
NativeModules can be created from any number of threads. In the legacy system, `ModuleHolder`, the class responsible for creating NativeModules, has built-in concurrency control to ensure that NativeModule creation is thread-safe. This diff introduces that thread-safety to the TurboModule infra. Basically, after this diff, if `n` threads race to create a TurboModule x, only the first thread will create x. All other threads will wait until x is created.
Changelog:
[Android][Fixed] - Make TurboModule creation thread-safe
Reviewed By: mdvacca
Differential Revision: D20659799
fbshipit-source-id: 2b720fe1ea49e40ae0d6dae50d422f23a6f45520