test: change callback function to arrow function

PR-URL: #17698
Reviewed-By: Yosuke Furukawa <yosuke.furukawa@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: you12724

test/parallel/test-http-connect.js

@@ -21,9 +21,9 @@ server.on('connect', common.mustCall((req, socket, firstBodyChunk) => {
   }));
 }));
 
-server.listen(0, common.mustCall(function() {
+server.listen(0, common.mustCall(() => {
   const req = http.request({
-    port: this.address().port,
+    port: server.address().port,
     method: 'CONNECT',
     path: 'google.com:443'
   }, common.mustNotCall());