test: update test-cluster-shared-handle-bind-error

- Remove assignment of this to variable.
- Add common.mustCall() as needed.
- Move from var to const.

PR-URL: https://github.com/nodejs/node/pull/10547
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/test-cluster-shared-handle-bind-error.js

@@ -1,25 +1,26 @@
 'use strict';
-var common = require('../common');
-var assert = require('assert');
-var cluster = require('cluster');
-var net = require('net');
+const common = require('../common');
+const assert = require('assert');
+const cluster = require('cluster');
+const net = require('net');
 
 if (cluster.isMaster) {
   // Master opens and binds the socket and shares it with the worker.
   cluster.schedulingPolicy = cluster.SCHED_NONE;
   // Hog the TCP port so that when the worker tries to bind, it'll fail.
-  net.createServer(common.fail).listen(common.PORT, function() {
-    var server = this;
-    var worker = cluster.fork();
-    worker.on('exit', common.mustCall(function(exitCode) {
+  const server = net.createServer(common.fail);
+
+  server.listen(common.PORT, common.mustCall(() => {
+    const worker = cluster.fork();
+    worker.on('exit', common.mustCall((exitCode) => {
       assert.strictEqual(exitCode, 0);
       server.close();
     }));
-  });
+  }));
 } else {
-  var s = net.createServer(common.fail);
+  const s = net.createServer(common.fail);
   s.listen(common.PORT, common.fail.bind(null, 'listen should have failed'));
-  s.on('error', common.mustCall(function(err) {
+  s.on('error', common.mustCall((err) => {
     assert.strictEqual(err.code, 'EADDRINUSE');
     process.disconnect();
   }));