lib: move DEP0021 to end of life

Server.listenFD() has been runtime deprecated since
Node 0.7.12. This commit moves the deprecation to
end-of-life.

PR-URL: https://github.com/nodejs/node/pull/27127


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>