For testing: use different servers with different ports for nextjs app

Author: GoodDayForSurf

packages/devextreme-cli/testing/constants.js

@@ -30,8 +30,8 @@ exports.viewports = {
 };
 
 exports.themes = {
-/*    material: 'material.blue',
-    generic: 'generic',*/
+    material: 'material.blue',
+    generic: 'generic',
     fluent: 'fluent.blue'
 };