Write a spec to verify a bug related to jQuery.ajax method

The definition file does not leverage the returned value of $.ajax() method well. The official syntax is

```
jqXHR.then(function( data, textStatus, jqXHR ) {}, function( jqXHR, textStatus, errorThrown ) {});
```

(From: http://api.jquery.com/jQuery.ajax/)

But, it does not get compilation.