Add import required for Stackblitz.

Author: DeborahK

APM-Final/src/polyfills.ts

@@ -74,6 +74,8 @@
  */
 import 'zone.js/dist/zone';  // Included with Angular CLI.
 
+/* Required for Stackblitz */
+import 'core-js/es7/reflect';
 
 /***************************************************************************************************
  * APPLICATION IMPORTS