n-api: handle reference delete before finalize

Crashes were reported during finalization due to
the memory for a reference being deleted and the
finalizer running after the deletion.

This change ensures the deletion of the memory for
the reference only occurs after the finalizer has run.

Fixes: https://github.com/nodejs/node-addon-api/issues/393

PR-URL: https://github.com/nodejs/node/pull/24494


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>