test: explicitly add localize polyfill

Since this polyfill is no longer automatically added, the internal
test projects should explicitly add it in `polyfills.ts`.

See: d6a3403

Author: jkrems

modules/testing/builder/projects/hello-world-app/src/polyfills.ts

@@ -68,3 +68,5 @@ import 'zone.js'; // Included with Angular CLI.
 /***************************************************************************************************
  * APPLICATION IMPORTS
  */
+
+import '@angular/localize/init';

packages/angular_devkit/build_webpack/test/angular-app/src/polyfills.ts

@@ -40,3 +40,5 @@ import 'zone.js'; // Included with Angular CLI.
 /***************************************************************************************************
  * APPLICATION IMPORTS
  */
+
+import '@angular/localize/init';