net/id_test: refactor tests into own func
net: have an explicit IdentifyConn on dial

- Make sure we call IdentifyConn on dialed out conns
- we wait until the identify is **done** before return
- on listening case, we can also wait.
- tests now make sure dial does wait.
- tests now make sure we can wait on listening case.
net/mocknet: fixed listenaddrs (misrepresenting)

some dht tests signaled "sending peer empty addresses"
which would then cause a failure. this was a misrepresentation
on the part of mocknet. it has been corrected.