timers: attach listOnTimeout function to TimerWrap

Make the listOnTimeout function inline by attaching it to the TimeWrap
prototype.
It improves insertion and cancellation time of unpooled timers by 18%
and 28% respectively.

PR-URL: https://github.com/nodejs/node/pull/18388


Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Weijia Wang <starkwang@126.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>