Remove duplicate compiling of task when: statements

Fixes #8538

lib/ansible/playbook/play.py

@@ -563,12 +563,6 @@ class Play(object):
                 if 'vars' in x:
                     task_vars = utils.combine_vars(task_vars, x['vars'])
 
-                if 'when' in x:
-                    if isinstance(x['when'], (basestring, bool)):
-                        included_additional_conditions.append(x['when'])
-                    elif isinstance(x['when'], list):
-                        included_additional_conditions.extend(x['when'])
-
                 new_role = None
                 if 'role_name' in x:
                     new_role = x['role_name']

lib/ansible/playbook/task.py

@@ -300,6 +300,7 @@ class Task(object):
         self.tags.extend(import_tags)
 
         if additional_conditions:
-            new_conditions = additional_conditions
+            new_conditions = additional_conditions[:]
-            new_conditions.append(self.when)
+            if self.when:
+                new_conditions.append(self.when)
             self.when = new_conditions