bpo-35444: Unify and optimize the helper for getting a builtin object. (GH-11047)

This speeds up pickling of some iterators.

This fixes also error handling in pickling methods when fail to
look up builtin "getattr".

Python/ceval.c

@@ -4437,6 +4437,20 @@ PyEval_GetBuiltins(void)
         return current_frame->f_builtins;
 }
 
+/* Convenience function to get a builtin from its name */
+PyObject *
+_PyEval_GetBuiltinId(_Py_Identifier *name)
+{
+    PyObject *attr = _PyDict_GetItemIdWithError(PyEval_GetBuiltins(), name);
+    if (attr) {
+        Py_INCREF(attr);
+    }
+    else if (!PyErr_Occurred()) {
+        PyErr_SetObject(PyExc_AttributeError, _PyUnicode_FromId(name));
+    }
+    return attr;
+}
+
 PyObject *
 PyEval_GetLocals(void)
 {