worker: add ports property to MessageEvents

Add `ev.ports` for spec compliancy.

Since we only emit the raw `data` value, and only create the
`MessageEvent` instance if there are EventTarget-style listeners,
we store the ports list temporarily on the MessagePort object itself,
so that we can look it up when we need to create the event object.

Fixes: https://github.com/nodejs/node/issues/37358

PR-URL: https://github.com/nodejs/node/pull/37538


Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>