Revert "fix(router): do not finish bootstrap until all the routes are resolved (#14608)"

This reverts commit 2a191cae2d.

modules/@angular/common/src/location/platform_location.ts

@@ -6,7 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {InjectionToken} from '@angular/core';
 /**
  * This class should not be used directly by an application developer. Instead, use
  * {@link Location}.
@@ -51,12 +50,6 @@ export abstract class PlatformLocation {
   abstract back(): void;
 }
 
-/**
- * @whatItDoes indicates when a location is initialized
- * @experimental
- */
-export const LOCATION_INITIALIZED = new InjectionToken<Promise<any>>('Location Initialized');
-
 /**
  * A serializable version of the event from onPopState or onHashChange
  *