test: add test case for missing branch

- The case of id is string, flags is number
- The case of flags is not 0

PR-URL: https://github.com/nodejs/node/pull/17418


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>