Tests: 8XXX used as default port range.

After the launch of the project, the testing infrastructure was shared with
nginx project in some cases.  To avoid port overlap, a decision was made
to shift the port range for Unit tests.  This problem was resolved a long time
ago and is no longer relevant, so it is now safe to use port 8XXX range as the
default, as it is more appropriate for testing purposes.

test/node/write_callback/app.js

@@ -9,4 +9,4 @@ require('http').createServer(function (req, res) {
             fs.appendFile('callback', '', function() {});
     });
     res.end(a);
-}).listen(7080);
+}).listen(8080);