src: use MaybeLocal.ToLocal instead of IsEmpty

This commit suggest using MaybeLocal.ToLocal and passing in the
Local<Function> fn.

The motivation for doing this is that the following
MaybeLocal.ToLocalChecked call can then be avoided.

PR-URL: https://github.com/nodejs/node/pull/33312


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>