_PyObject_FastCallKeywords() now checks the result

Issue #python#27830, Issue python#29259.

Author: vstinner

Objects/abstract.c

@@ -2539,6 +2539,8 @@ _PyObject_FastCallKeywords(PyObject *callable, PyObject **stack, Py_ssize_t narg
         Py_DECREF(argtuple);
         Py_XDECREF(kwdict);
 
+        result = _Py_CheckFunctionResult(callable, result, NULL);
+
     exit:
         Py_LeaveRecursiveCall();
         return result;