Don't update state before summary. It should be consistent

Since we know when an object's state can change, we don't need
to update the state of all objects for consistency.

buildstream/_stream.py

@@ -1018,17 +1018,6 @@ class Stream():
 
         _, status = self._scheduler.run(self.queues)
 
-        # Force update element states after a run, such that the summary
-        # is more coherent
-        try:
-            for element in self.total_elements:
-                element._update_state()
-        except BstError as e:
-            self._message(MessageType.ERROR, "Error resolving final state", detail=str(e))
-            set_last_task_error(e.domain, e.reason)
-        except Exception as e:   # pylint: disable=broad-except
-            self._message(MessageType.BUG, "Unhandled exception while resolving final state", detail=str(e))
-
         if status == SchedStatus.ERROR:
             raise StreamError()
         elif status == SchedStatus.TERMINATED: