This commit adds the `provideLocationMocks()` function that returns mocks for the `Location` and `LocationStrategy` classes. This function can be used in tests to configure an environment where it's possible to fire simulated location events (helpful when testing Router configuration).
PR Close#47674
Prior to this change we had a MockLocationStrategy to replace the Path and Hash Location Strategies. However, there wasn't a good way to test the PlatformLocation which is needed for doing things such as setting history.state, using back()/forward(), etc.
PR Close#30055