src: expose ArrayBuffer version of Buffer::New()

This can be useful to create `Buffer` instances for already-existing
`ArrayBuffer`s, e.g. ones created manually from a backing store
with a free callback (of which our variant in the public API has
some limitations).

PR-URL: https://github.com/nodejs/node/pull/30476


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>