Adds two new helper functions that can be used when unit testing Angular services
that depend upon upgraded AngularJS services, or vice versa.
The functions return a module (AngularJS or NgModule) that is configured to wire up
the Angular and AngularJS injectors without the need to actually bootstrap a full
hybrid application.
This makes it simpler and faster to unit test services.
PR Close#16848
3fb78aaacc