🐛 Bug Report — fetch fails locally with custom port on HTTPS

I'm trying to do a fetch request from a Worker to a local dev server over HTTPS and getting a 500 error.

The URL is something like this:
```
https://127.0.0.1:5555/some/path/etc
```
Wrangler only outputs this:
```
[wrangler:err] Error: internal error
at (stack trace)
[wrangler:inf] GET /some/path/etc 500 Internal Server Error (19ms)
```

The request works as expected when disabling HTTPS in the dev server.

This is a bit of a pain because the server needs HTTPS for other features. So now we're required to manually enable/disable HTTPS when testing a single endpoint that is called from the Worker.

I'm getting this warning from Wrangler:

> WARNING: known issue with `fetch()` requests to custom HTTPS ports in **published** Workers

Which refers to published workers, and I'm testing this locally.