lib: move duplicate spliceOne into internal/util

lib/url.js and lib/events.js are using the same spliceOne function.
This change is to move it into the internal/util for avoiding duplicate
code.

PR-URL: https://github.com/nodejs/node/pull/16221


Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>