Don't split args out unless we're parsing module args using the new style

Fixes #12331

lib/ansible/parsing/mod_args.py

@@ -150,8 +150,7 @@ class ModuleArgsParser:
 
             # this can occasionally happen, simplify
             if args and 'args' in args:
-            tmp_args = args['args']
-            del args['args']
+                tmp_args = args.pop('args')
                 if isinstance(tmp_args, string_types):
                     tmp_args = parse_kv(tmp_args)
                 args.update(tmp_args)