Use builtins_module instead of BUILTINS

jedi/evaluate/__init__.py

@@ -111,12 +111,10 @@ class Evaluator(object):
 
         self.reset_recursion_limitations()
 
-        # Constants
-        # TODO move to get_builtins_module
-        self.BUILTINS = compiled.get_special_object(self, 'BUILTINS')
-
-    def get_builtins_module(self):
-        return self.BUILTINS
+    @property
+    @evaluator_function_cache()
+    def builtins_module(self):
+        return compiled.get_special_object(self, 'BUILTINS')
 
     def reset_recursion_limitations(self):
         self.recursion_detector = recursion.RecursionDetector()