Devtunnel rewrites `localhost` location headers

[Jafferwaffer]

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Summary

When a server behind devtunnel sends an HTTP redirect to http://localhost:3000/some-url, devtunnel rewrites the Location header to something like:

Location: https://mytunnel.devtunnels.ms:3000/some-url

This breaks the redirect if port 3000 is not forwarded.

In my express server (which is being port forwarded) I am calling res.redirect('http://localhost:3000/some-url') but in the browser the location header is being rewritten as described above.

Steps to Reproduce

1. Start a devtunnel on a port other than 3000.

2. Serve a backend on that port that does:

   res.redirect('http://localhost:3000/some-url');
   

3. Visit the devtunnel URL and trigger the redirect.

4. The browser is redirected to https://<your-tunnel>:3000/some-url and fails to load.

Expected Behavior

Redirects to localhost should remain unchanged