chore(ngUpgrade): Move into Angular2

This is moving ngUpgrade into the main repository per #4838.
The ngUpgrade is published from the main import consistent with
https://docs.google.com/document/d/1rbVTKTYLz6p2smQNYI8h4-QN-m2PS6F3iQIDmSzn0Ww/edit#heading=h.6cxvr9awtf5r
Closes #4931

test-main.js

@@ -14,8 +14,7 @@ System.config({
     'benchpress/*': 'dist/js/dev/es5/benchpress/*.js',
     'angular2/*': 'dist/js/dev/es5/angular2/*.js',
     'angular2_material/*': 'dist/js/dev/es5/angular2_material/*.js',
-    '@reactivex/rxjs/*': 'node_modules/@reactivex/rxjs/*.js',
-    'upgrade/*': 'dist/js/dev/es5/upgrade/*.js'
+    '@reactivex/rxjs/*': 'node_modules/@reactivex/rxjs/*.js'
   }
 });