Smart group rebuild does not work for parent groups

GroupContactCache.php does not create or update the smart group cache for parent groups, i.e. groups with condition (children IS NOT NULL).

It works correctly for dynamic groups (saved_search_id IS NOT NULL).

Steps to reproduce:
1) Clear alle the caches of civicrm
2) Create a parent group of some child group
3) Add a contact to the child group
4) Open the contact and go to the tab "groups" and open the list of "dynamic groups"
5) The parent group is not shown in this list