chore(lint): Added license headers to most TypeScript files

Relates to #9380

modules/@angular/common/testing.ts

@@ -1,2 +1,10 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
 export {SpyLocation} from './testing/location_mock';
 export {MockLocationStrategy} from './testing/mock_location_strategy';