inspector: proper WS URLs when bound to 0.0.0.0

JSON target list response will now return appropriate IP address
for instances listening on 0.0.0.0.

Refs: https://github.com/nodejs/node/issues/11591
PR-URL: https://github.com/nodejs/node/pull/11755


Reviewed-By: James Snell <jasnell@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>