fix(turbopack): Fix sourcemap path on windows (#78453)
### What?
Fix source map path on Windows by fixing the `url_to_file` function.
Note: This PR is based on https://github.com/vercel/next.js/pull/78430 by @JustSuperHuman
### Why?
### How?
- Closes PACK-4217
- Closes PACK-3924
- Closes https://github.com/vercel/next.js/issues/72789
