Add work-around for ssh pty race condition.

This should minimize loss of stdout when using
a pty and connecting with ssh or paramiko_ssh.

lib/ansible/plugins/action/__init__.py

@@ -711,6 +711,9 @@ class ActionBase(with_metaclass(ABCMeta, object)):
         if self._connection.allow_executable:
             if executable is None:
                 executable = self._play_context.executable
+                # mitigation for SSH race which can drop stdout (https://github.com/ansible/ansible/issues/13876)
+                # only applied for the default executable to avoid interfering with the raw action
+                cmd = self._connection._shell.append_command(cmd, 'sleep 0')
             if executable:
                 cmd = executable + ' -c ' + pipes.quote(cmd)