bpo-41870: Avoid the test when nargs=0 (GH-22462)

Objects/boolobject.c

@@ -72,10 +72,10 @@ bool_vectorcall(PyObject *type, PyObject * const*args,
     assert(PyType_Check(type));
     if (nargs) {
         ok = PyObject_IsTrue(args[0]);
-    }
         if (ok < 0) {
             return NULL;
         }
+    }
     return PyBool_FromLong(ok);
 }