bec1854cc0 introduced a regression:
when sorting a tree model, children items would not follow the sorted
parents any more (they wouldn't be remapped correctly), resulting
in crashes.
So, the fix needs more reasoning; let's revert the fix,
but leave the original test around for any subsequent attempt, and
introduce a new test which looks for the right behavior when
sorting trees.
This commit partially reverts bec1854cc0.
Task-number: QTBUG-43827
Change-Id: Ic83ac53aef639f870f6c36a8b4b2992f5b485b13
Reviewed-by: David Faure <david.faure@kdab.com>
Reviewed-by: Volker Krause <volker.krause@kdab.com>
e9ad46ed41