fix: correct imports for AriaLive test

Author: jelbourn

src/core/live-announcer/live-announcer.spec.ts

@@ -1,4 +1,8 @@
 import {
+  it,
+  describe,
+  expect,
+  beforeEach,
   inject,
   TestComponentBuilder,
   ComponentFixture,
@@ -7,12 +11,6 @@ import {
   tick,
   beforeEachProviders
 } from 'angular2/testing';
-import {
-  it,
-  describe,
-  expect,
-  beforeEach,
-} from '../../core/facade/testing';
 import {Component} from 'angular2/core';
 import {By} from 'angular2/platform/browser';
 import {MdLiveAnnouncer} from './live-announcer';