async_hooks: improve property descriptors in als.bind

The length property should be non enumerable to match behavior of
normal functions.

The asyncResource property is enumerable and therefore it should be
also writable to avoid issues like there:
https://github.com/nodejs/node/pull/30932#discussion_r379679982

Both properties should be configurable.

Refs: https://github.com/nodejs/node/pull/34574

PR-URL: https://github.com/nodejs/node/pull/34620


Reviewed-By: Andrey Pechkurov <apechkurov@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>