Enable userland snapshotting in Node.js

Refs https://github.com/electron/electron/pull/35999.

Refs https://github.com/nodejs/node/pull/38905

Node.js added support for user-land runtime snapshots via `--build-snapshot` and `--snapshot-blob`. We don't support that for the moment because it will require a bit of work on our end, so it's being marked here as a follow-up in order to enable merge of the v18 upgrade PR.