fix(bundles): remove polyfills from angular2.js bundle

BREAKING CHANGE:

Previously `angular2.js`, `angular2.min.js` and `angular2.dev.js` bundles
would have zone.js and reflect-metadata pre-appended. New bundles don't
contain zone.js nor reflect-metadata - those external dependencies can
be easily loaded into a browser using `angular2-polyfills.js`

Closes #5881

tools/broccoli/html-replace/SCRIPTS.html

@@ -16,6 +16,7 @@
     }
   });
 </script>
+<script src="/bundle/angular2-polyfills.js"></script>
 <script src="/bundle/angular2.dev.js"></script>
 <script src="/bundle/http.js"></script>
 <script src="/bundle/router.dev.js"></script>

tools/broccoli/html-replace/SCRIPTS_benchmarks.html

@@ -17,6 +17,7 @@
     }
   });
 </script>
+<script src="/bundle/angular2-polyfills.js"></script>
 <script src="/bundle/angular2.dev.js"></script>
 <script>
   var filename = '@@PATH/@@FILENAME';