DIR builtin: sort returned list (if a list)

Author: cosminbasca

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/BuiltinFunctions.java

@@ -498,8 +498,13 @@ Object locals(VirtualFrame frame, @SuppressWarnings("unused") Object object,
 
         @Specialization(guards = "!isNoValue(object)")
         Object dir(VirtualFrame frame, Object object,
+                        @Cached ListBuiltins.ListSortNode sortNode,
                         @Cached("create(__DIR__)") LookupAndCallUnaryNode dirNode) {
-            return dirNode.executeObject(frame, object);
+            Object list = dirNode.executeObject(frame, object);
+            if (list instanceof PList) {
+                sortNode.sort(frame, (PList) list);
+            }
+            return list;
         }
     }