Revert "lib,src: add unix socket getsockname/getpeername"

This reverts commit 6cd0e266.
This reverts commit 7a999a13.
This reverts commit f3375954.

It turns out that on Windows, uv_pipe_getsockname() is a no-op for
client sockets.  It slipped through testing because of a CI snafu.

PR-URL: https://github.com/nodejs/node/pull/2584


Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>