fix($parse): make the window check in ensureSafeObject IE8 friendly

Author: IgorMinar

src/ng/parse.js

@@ -45,7 +45,7 @@ function ensureSafeObject(obj, fullExpression) {
           'Referencing Function in Angular expressions is disallowed! Expression: {0}',
           fullExpression);
     } else if (// isWindow(obj)
-        obj.window === obj) {
+        obj.document && obj.location && obj.alert && obj.setInterval) {
       throw $parseMinErr('isecwindow',
           'Referencing the Window in Angular expressions is disallowed! Expression: {0}',
           fullExpression);