crypto: fix key object wrapping in sync keygen

PR-URL: https://github.com/nodejs/node/pull/25326
Fixes: https://github.com/nodejs/node/issues/25322


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>