refactor(animations): move MockAnimationPlayer back into core (#9966)

Closes #9966

modules/@angular/platform-browser/testing/mock_animation_player.ts

@@ -1,64 +0,0 @@
-/**
- * @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 {AnimationPlayer} from '../../core/src/animation/animation_player';
-import {isPresent} from '../../core/src/facade/lang';
-
-export class MockAnimationPlayer implements AnimationPlayer {
-  private _subscriptions: any[] /** TODO #9100 */ = [];
-  private _finished = false;
-  private _destroyed = false;
-  private _started: boolean = false;
-
-  public parentPlayer: AnimationPlayer = null;
-
-  public log: any[] /** TODO #9100 */ = [];
-
-  private _onfinish(): void {
-    if (!this._finished) {
-      this._finished = true;
-      this.log.push('finish');
-
-      this._subscriptions.forEach((entry) => { entry(); });
-      this._subscriptions = [];
-      if (!isPresent(this.parentPlayer)) {
-        this.destroy();
-      }
-    }
-  }
-
-  init(): void { this.log.push('init'); }
-
-  onDone(fn: Function): void { this._subscriptions.push(fn); }
-
-  hasStarted() { return this._started; }
-
-  play(): void {
-    this._started = true;
-    this.log.push('play');
-  }
-
-  pause(): void { this.log.push('pause'); }
-
-  restart(): void { this.log.push('restart'); }
-
-  finish(): void { this._onfinish(); }
-
-  reset(): void { this.log.push('reset'); }
-
-  destroy(): void {
-    if (!this._destroyed) {
-      this._destroyed = true;
-      this.finish();
-      this.log.push('destroy');
-    }
-  }
-
-  setPosition(p: any /** TODO #9100 */): void {}
-  getPosition(): number { return 0; }
-}