Fix notification timing issue by sending in the latter of 2 events (#12110)

* Track host_status_counts and use that to process notifications

* Remove now unused setting

* Back out changes to callback class not needed after all

* Skirt the need for duck typing by leaning on the cached field

* Delete tests for deleted task

* Revert "Back out changes to callback class not needed after all"

This reverts commit 3b8ae350d218991d42bffd65ce4baac6f41926b2.

* Directly hardcode stats_event_type for callback class

* Fire notifications if stats event was never sent

* Remove test content for deleted methods

* Add placeholder for when no hosts matched

* Make field default be None, denote events processed with empty dict

* Make UI process null value for host_status_counts

* Fix tracking of EOF dispatch for system jobs

* Reorganize EVENT_MAP into class properties

* Consolidate conditional I missed from EVENT_MAP refactor

* Give up on the null condition, also applies for empty hosts

* Remove cls position argument not being used

* Move wrapup method out of class, add tests

awx/main/utils/update_model.py

@@ -7,14 +7,17 @@ import time
 logger = logging.getLogger('awx.main.tasks.utils')
 
 
-def update_model(model, pk, _attempt=0, _max_attempts=5, **updates):
+def update_model(model, pk, _attempt=0, _max_attempts=5, select_for_update=False, **updates):
     """Reload the model instance from the database and update the
     given fields.
     """
     try:
         with transaction.atomic():
             # Retrieve the model instance.
-            instance = model.objects.get(pk=pk)
+            if select_for_update:
+                instance = model.objects.select_for_update().get(pk=pk)
+            else:
+                instance = model.objects.get(pk=pk)
 
             # Update the appropriate fields and save the model
             # instance, then return the new instance.