lib: make queueMicrotask faster

No longer create an additional scope within queueMicrotask
in order to improve performance.

PR-URL: https://github.com/nodejs/node/pull/27032


Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>