Adding aliases for field attributes and renaming async attribute (#33141)

* Adding aliases for field attributes and renaming async attribute

As of Python 3.7, the use of async raises an error, whereas before the use
of the reserved word was ignored. This adds an alias field for field attrs
so that both async and async_val (interally) work. This allows us to be
backwards-compatible with 3rd party plugins that may still reference Task.async,
but for the core engine to work on Py3.7+.

* Remove files fixed for 'async' usage from the python 3.7 skip list

test/units/plugins/action/test_action.py

@@ -75,12 +75,12 @@ class TestActionBase(unittest.TestCase):
 
         play_context = PlayContext()
 
-        mock_task.async = None
+        mock_task.async_val = None
         action_base = DerivedActionBase(mock_task, mock_connection, play_context, None, None, None)
         results = action_base.run()
         self.assertEqual(results, dict())
 
-        mock_task.async = 0
+        mock_task.async_val = 0
         action_base = DerivedActionBase(mock_task, mock_connection, play_context, None, None, None)
         results = action_base.run()
         self.assertEqual(results, {})
@@ -92,7 +92,7 @@ class TestActionBase(unittest.TestCase):
         # create our fake task
         mock_task = MagicMock()
         mock_task.action = "copy"
-        mock_task.async = 0
+        mock_task.async_val = 0
 
         # create a mock connection, so we don't actually try and connect to things
         mock_connection = MagicMock()

test/units/plugins/action/test_raw.py

@@ -43,7 +43,7 @@ class TestCopyResultExclude(unittest.TestCase):
 
         play_context = Mock()
         task = MagicMock(Task)
-        task.async = False
+        task.async_val = False
         connection = Mock()
 
         task.args = {'_raw_params': 'Args1'}
@@ -60,7 +60,7 @@ class TestCopyResultExclude(unittest.TestCase):
 
         play_context = Mock()
         task = MagicMock(Task)
-        task.async = False
+        task.async_val = False
         connection = Mock()
 
         task.args = {'_raw_params': 'Args1'}
@@ -75,7 +75,7 @@ class TestCopyResultExclude(unittest.TestCase):
 
         play_context = Mock()
         task = MagicMock(Task)
-        task.async = False
+        task.async_val = False
         connection = Mock()
 
         task.args = {'_raw_params': 'Args1'}
@@ -92,7 +92,7 @@ class TestCopyResultExclude(unittest.TestCase):
 
         play_context = Mock()
         task = MagicMock(Task)
-        task.async = False
+        task.async_val = False
         connection = Mock()
 
         task.args = {'_raw_params': 'Args1'}

test/units/plugins/action/test_synchronize.py

@@ -46,7 +46,7 @@ class TaskMock(object):
     args = {'src': u'/tmp/deleteme',
             'dest': '/tmp/deleteme',
             'rsync_path': 'rsync'}
-    async = None
+    async_val = None
     become = None
     become_user = None
     become_method = None