As a hacky solution to http:crbug.com/904609I added a ChromeOS switch to ignore ethernet connections when deciding whether to scan for a tether host. This allowed us to deploy tests via ssh without the requisite ethernet connection block our e2e tests. See
https://chromium-review.googlesource.com/c/chromium/src/+/1332693 and
https://chromium-review.googlesource.com/c/chromium/src/+/1334206 for implementation.

In order to avoid using a testing only ChromeOS switch, we should get rid of that infrastructure entirely and use a tool from flimflam that can accomplish the same result.