Rollback should clean Selection caches

After a transaction rollback the Selection caches should be flushed.

This is not the case and this is responsible for WARN log like

 WARN  [Selection] Existing fragment missing: 8c9f1cb1-d546-4072-9d17-10fc43138a6a

When accessing invalid cache entries.

To reproduce create a unit test CoreFeature, that creates docs and rollback.
The afterTearDown method will cleanup the session with a removeChildren("/"), the Selection cache contains the list of documents that are not present because of the rollback.