tls: named anonymous functions in _tls_wrap.js

PR-URL: https://github.com/nodejs/node/pull/21756
Refs: https://github.com/nodejs/node/issues/8913


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>