refactor(various): remove a few lingering but unused deprecated apis (#10896)

Removes deprecated APPLICATION_COMMON_PROVIDERS, as well as some
internal apis that were deprecated.

modules/@angular/core/testing/testing_internal.ts

@@ -17,7 +17,6 @@ export {MockAnimationPlayer} from './mock_animation_player';
 export {inject} from './test_bed';
 export * from './logger';
 export * from './ng_zone_mock';
-export * from './mock_application_ref';
 export * from './test_component_builder';
 
 export var proxy: ClassDecorator = (t: any /** TODO #9100 */) => t;