net: don't normalize twice in Socket#connect()

Split up Socket#connect() so that we don't call normalizeArgs() twice
when invoking net.connect() or net.createConnection().

PR-URL: #12342
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/net.js

@@ -73,7 +73,7 @@ function connect() {
     socket.setTimeout(options.timeout);
   }
 
-  return Socket.prototype.connect.call(socket, options, cb);
+  return realConnect.call(socket, options, cb);
 }
 
 
@@ -899,7 +899,11 @@ Socket.prototype.connect = function() {
   const normalized = normalizeArgs(args);
   const options = normalized[0];
   const cb = normalized[1];
+  return realConnect.call(this, options, cb);
+};
+
 
+function realConnect(options, cb) {
   if (this.write !== Socket.prototype.write)
     this.write = Socket.prototype.write;
 
@@ -940,7 +944,7 @@ Socket.prototype.connect = function() {
     lookupAndConnect(this, options);
   }
   return this;
-};
+}
 
 
 function lookupAndConnect(self, options) {