test: replace anonymous function with arrow function

test/parallel/test-https-client-resume.js

@@ -38,7 +38,7 @@ const options = {
 };
 
 // create server
-const server = https.createServer(options, common.mustCall(function(req, res) {
+const server = https.createServer(options, common.mustCall((req, res) => {
   res.end('Goodbye');
 }, 2));
 
@@ -49,7 +49,7 @@ server.listen(0, function() {
   const client1 = tls.connect({
     port: this.address().port,
     rejectUnauthorized: false
-  }, function() {
+  }, () => {
     console.log('connect1');
     assert.ok(!client1.isSessionReused(), 'Session *should not* be reused.');
     session1 = client1.getSession();
@@ -58,7 +58,7 @@ server.listen(0, function() {
                   '\r\n');
   });
 
-  client1.on('close', function() {
+  client1.on('close', () => {
     console.log('close1');
 
     const opts = {
@@ -67,15 +67,15 @@ server.listen(0, function() {
       session: session1
     };
 
-    const client2 = tls.connect(opts, function() {
+    const client2 = tls.connect(opts, () => {
       console.log('connect2');
       assert.ok(client2.isSessionReused(), 'Session *should* be reused.');
       client2.write('GET / HTTP/1.0\r\n' +
                     'Server: 127.0.0.1\r\n' +
                     '\r\n');
     });
 
-    client2.on('close', function() {
+    client2.on('close', () => {
       console.log('close2');
       server.close();
     });