* Add test_spec for FCM
* FIRMessagingRemoteNotificationsProxyTest - don't use OCMPartialMock([UIApplication sharedApplication]) to avoid crashing tests on iOS 8 (#3094)
* Migrate Firebase off @import statements
* - Migrate tests and test utils from @import to #import.
- Update Xcode projects for tests to explicitly link in framework deps.
- Update check_no_module_imports.sh to look for @imports in tests/test utils/
integration tests.
* Ensure check_no_module_imports.sh explicitly exits with code 0 on success.