allow passing arbitrary node options

I'm writing some miniflare tests in uvu and needed this in my package.json:

```
"test": "NODE_OPTIONS=\"--experimental-vm-modules --no-warnings\" uvu -r tsm tests -i setup"
```

It would be fantastic if this library could support `--experimental-vm-modules` so I can go back to loadr <3

Start with the package.json test command shown in the issue and inspect how loadr is used with uvu and tsm. Reproduce the Miniflare test scenario using --experimental-vm-modules and --no-warnings, then verify that arbitrary Node options work as requested without breaking the existing loader behavior.

Written by the indexing model from the issue text.