Make sure tasks from a role see their defaults above all others

Fixes #12081

lib/ansible/vars/__init__.py

@@ -183,6 +183,12 @@ class VariableManager:
             for role in play.get_roles():
                 all_vars = self._combine_vars(all_vars, role.get_default_vars())
 
+            # if we have a task in this context, and that task has a role, make
+            # sure it sees its defaults above any other roles, as we previously
+            # (v1) made sure each task had a copy of its roles default vars
+            if task and task._role is not None:
+                all_vars = self._combine_vars(all_vars, task._role.get_default_vars())
+
         if host:
             # next, if a host is specified, we load any vars from group_vars
             # files and then any vars from host_vars files which may apply to