add template url argument to $includeContentRequested event

#8453
I think it is cleaner to use jasmine spies for this kind of test.  Something like this:

```js
it('should fire $includeContentLoaded with the template url as the second parameter', inject(function($rootScope, $compile, $templateCache) {
    var handlerSpy = jasmine.createSpy('handler');
    $templateCache.put('/some/template.html', [200, '', {}]);
    $rootScope.$on('$includeContentLoaded', handlerSpy);
    element = $compile('<div><ng:include src="\'/some/template.html\'"></ng:include></div>')($rootScope);
    $rootScope.$digest();
    expect(handlerSpy).toHaveBeenCalledWith(jasmine.any(Object), '/some/template.html');
  }));
```