src: isolate->Dispose() order consistency

PR-URL: https://github.com/nodejs/node/pull/30181


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: David Carlier <devnexen@gmail.com>