test(aio): move reflect-metadata polyfills to test.ts (#23234)

This resolves https://github.com/angular/angular-cli/issues/10333 and nicely cleans up the code.

PR Close #23234

aio/src/environments/environment.ts

@@ -4,12 +4,10 @@
 // The list of which env maps to which file can be found in `angular-cli.json`.
 
 
-// Reflect.metadata polyfill is only needed in the JIT/dev mode.
-//
-// In order to load these polyfills early enough (before app code), polyfill.ts imports this file to
-// to change the order in the final bundle.
-import 'core-js/es6/reflect';
-import 'core-js/es7/reflect';
+// Reflect.metadata polyfill is only needed in the JIT, which use use only for tests
+// to make the unit tests work we load these polyfills in tests.ts instead
+// import 'core-js/es6/reflect';
+// import 'core-js/es7/reflect';
 
 
 export const environment = {

aio/src/polyfills.ts

@@ -27,9 +27,6 @@
  * and executed before the rest of the application files are executed.
  */
 
-/** HACK: force import of environment.ts/environment.prod.ts to load env specific polyfills */
-import './environments/environment';
-
 /** ALL Firefox browsers require the following to support `@angular/animation`. **/
 // import 'web-animations-js';  // Run `npm install --save web-animations-js`.
 

aio/src/test.ts

@@ -9,6 +9,10 @@ import {
 
 declare const require: any;
 
+// Reflect.metadata polyfill is only needed in the JIT mode which we use only for unit tests
+import 'core-js/es6/reflect';
+import 'core-js/es7/reflect';
+
 // First, initialize the Angular testing environment.
 getTestBed().initTestEnvironment(
     BrowserDynamicTestingModule,