test: changed function to arrow function

Convert callback functions that are anonymous
to arrow functions for better readability.
Also adjusted the `this` object in places where
that was required.

PR-URL: #32875
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: nimit95

test/parallel/test-net-after-close.js

@@ -24,14 +24,14 @@ const common = require('../common');
 const assert = require('assert');
 const net = require('net');
 
-const server = net.createServer(common.mustCall(function(s) {
+const server = net.createServer(common.mustCall((s) => {
   console.error('SERVER: got connection');
   s.end();
 }));
 
-server.listen(0, common.mustCall(function() {
-  const c = net.createConnection(this.address().port);
-  c.on('close', common.mustCall(function() {
+server.listen(0, common.mustCall(() => {
+  const c = net.createConnection(server.address().port);
+  c.on('close', common.mustCall(() => {
     console.error('connection closed');
     assert.strictEqual(c._handle, null);
     // Calling functions / accessing properties of a closed socket should not