[BUGFIX beta] Properly detect if the environment is Node.

* Check for both `process` and `window` when determining if the environment is Node.
* Closes #11679.

Author: brzpegasus

packages/loader/lib/main.js

@@ -2,7 +2,8 @@ var define, requireModule, require, requirejs, Ember;
 var mainContext = this;
 
 (function() {
-  var isNode = typeof process !== 'undefined' && {}.toString.call(process) === '[object process]';
+  var isNode = typeof window === 'undefined' &&
+    typeof process !== 'undefined' && {}.toString.call(process) === '[object process]';
 
   if (!isNode) {
     Ember = this.Ember = this.Ember || {};