remove some TODOs that are no longer issues

Author: mmalerba

src/cdk-experimental/testing/protractor.ts

@@ -6,9 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-// TODO(mmalerba): Should this file be part of `@angular/cdk-experimental/testing` or a separate
-//  package? It depends on protractor which we don't want to put in the deps for cdk-experimental.
-
 import {browser, by, element as protractorElement, ElementFinder} from 'protractor';
 
 import {

src/cdk-experimental/testing/testbed.ts

@@ -6,10 +6,6 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-// TODO(mmalerba): Should this file be part of `@angular/cdk-experimental/testing` or a separate
-//  package? It depends on `@angular/core/testing` which we don't want to put in the deps for
-//  cdk-experimental.
-
 import {
   dispatchFakeEvent,
   dispatchKeyboardEvent,

src/cdk-experimental/testing/tests/test-main-component.ts

@@ -30,13 +30,11 @@ export class TestMainComponent {
   username: string;
   counter: number;
   asyncCounter: number;
-  // TODO: remove '!'.
-  input!: string;
+  input: string;
   memo: string;
   testTools: string[];
   testMethods: string[];
-  // TODO: remove '!'.
-  _isHovering!: boolean;
+  _isHovering: boolean;
 
   onMouseOver() {
     this._isHovering = true;

src/cdk-experimental/testing/tests/test-sub-component.ts

@@ -20,8 +20,6 @@ import {ChangeDetectionStrategy, Component, Input, ViewEncapsulation} from '@ang
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class TestSubComponent {
-  // TODO: remove '!'.
-  @Input() title!: string;
-  // TODO: remove '!'.
-  @Input() items!: string[];
+  @Input() title: string;
+  @Input() items: string[];
 }