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

Relates to #9380

modules/@angular/forms/test/validators_spec.ts

@@ -1,3 +1,11 @@
+/**
+ * @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
+ */
+
 import {Log, fakeAsync, flushMicrotasks, tick} from '@angular/core/testing';
 import {afterEach, beforeEach, ddescribe, describe, expect, iit, it, xit} from '@angular/core/testing/testing_internal';
 import {AbstractControl, FormControl, Validators} from '@angular/forms';