Added further testing which fully covers what throws and what is undefined.

@guybedford we mentioned that some APIs were not exported by name (i.e. on, off, ...). Do you want to update this PR with them or do you plan to create a follow up PR?

Edits:

• we will probably wait for everything to be in before updating the unenv preset,
• could you please cc @petebacondarwin and I on native module updates.

Thx

@vicb process.on is a prototype property not an export, so process.on exists, but import { on } from 'node:process' does not. That is, we implement all these fine.