test: add dgram.Socket.prototype.bind's test

Test that an error is thrown when bind() is called on an already bound
socket.

PR-URL: https://github.com/nodejs/node/pull/10894


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Claudio Rodriguez <cjrodr@yahoo.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Italo A. Casas <me@italoacasas.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>