Add a regression test for https://github.com/iojs/io.js/issues/627.
Before the http_parser rollback to 2.3.0, the request callback was
called but an 'upgrade' event was not emitted, even though there is
an Upgrade header present in the request.
PR-URL: https://github.com/iojs/io.js/pull/628
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
