account for isolated job status

* We can not query the dispatcher running on isolated nodes to see if
the playbook is still running because that is the nature of isolated
nodes, they don't run the dispatcher nor do they run the message broker.
Therefore, we should query the control node that is arbitrating the
isolated work. If the control node process in the dispatcher is dead,
consider the iso job dead.

awx/main/models/unified_jobs.py

@@ -1361,7 +1361,7 @@ class UnifiedJob(PolymorphicModel, PasswordFieldsModel, CommonModelNameNotUnique
             timeout = 5
             try:
                 running = self.celery_task_id in ControlDispatcher(
-                    'dispatcher', self.execution_node
+                    'dispatcher', self.controller_node or self.execution_node
                 ).running(timeout=timeout)
             except socket.timeout:
                 logger.error('could not reach dispatcher on {} within {}s'.format(