Set correct completion time for finishing Tasks

On a TASK_FINISH event, set the task completion time to the time of
the event rather than the last time the task was stepped.  Resolves a
bug in the service where tasks that finish later than the simulator's
profiled runtime predicts get assigned the wrong completion time.

simulator.py

@@ -1232,7 +1232,7 @@ def __handle_task_finished(self, event: Event) -> None:
         # Remove the task from it's task graph's current placements
         del self._current_task_graph_placements[event.task.task_graph][event.task.id]
 
-        event.task.finish()
+        event.task.finish(event.time)
 
         # Log the TASK_FINISHED event into the CSV.
         self._finished_tasks += 1