test: add http upgrade header regression test

Add a regression test for #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: #628
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>

test/parallel/test-http-upgrade-yes-please.js

@@ -0,0 +1,22 @@
+'use strict';
+
+var assert = require('assert');
+var http = require('http');
+var net = require('net');
+
+var upgrades = 0;
+process.on('exit', function() { assert.equal(upgrades, 1); });
+
+http.createServer(assert.fail).listen(0, '127.0.0.1', function() {
+  this.on('upgrade', function(req, conn, head) {
+    conn.destroy();
+    this.close();
+    upgrades += 1;
+  });
+  var options = { host: this.address().address, port: this.address().port };
+  net.connect(options, function() {
+    this.write('GET / HTTP/1.1\r\n' +
+               'Upgrade: Yes, please.\r\n' +
+               '\r\n');
+  });
+});