test: use arrow functions in async-hooks tests

Convert all anonymous callback functions in `test/async-hooks/*.js`
to use arrow functions.

`writing-tests.md` states to use arrow functions when appropriate.

PR-URL: #30137
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

test/async-hooks/test-disable-in-init.js

@@ -7,7 +7,7 @@ const fs = require('fs');
 let nestedCall = false;
 
 async_hooks.createHook({
-  init: common.mustCall(function() {
+  init: common.mustCall(() => {
     nestedHook.disable();
     if (!nestedCall) {
       nestedCall = true;

test/async-hooks/test-graph.http.js

@@ -11,19 +11,19 @@ const http = require('http');
 const hooks = initHooks();
 hooks.enable();
 
-const server = http.createServer(common.mustCall(function(req, res) {
+const server = http.createServer(common.mustCall((req, res) => {
   res.end();
-  this.close(common.mustCall());
+  server.close(common.mustCall());
 }));
-server.listen(0, common.mustCall(function() {
+server.listen(0, common.mustCall(() => {
   http.get({
     host: '::1',
     family: 6,
     port: server.address().port
   }, common.mustCall());
 }));
 
-process.on('exit', function() {
+process.on('exit', () => {
   hooks.disable();
 
   verifyGraph(

test/async-hooks/test-graph.pipeconnect.js

@@ -12,9 +12,9 @@ tmpdir.refresh();
 const hooks = initHooks();
 hooks.enable();
 
-net.createServer(function(c) {
+const server = net.createServer((c) => {
   c.end();
-  this.close();
+  server.close();
 }).listen(common.PIPE, common.mustCall(onlisten));
 
 function onlisten() {

test/async-hooks/test-nexttick-default-trigger.js

@@ -14,11 +14,11 @@ hooks.enable();
 
 const rootAsyncId = async_hooks.executionAsyncId();
 
-process.nextTick(common.mustCall(function() {
+process.nextTick(common.mustCall(() => {
   assert.strictEqual(async_hooks.triggerAsyncId(), rootAsyncId);
 }));
 
-process.on('exit', function() {
+process.on('exit', () => {
   hooks.sanityCheck();
 
   const as = hooks.activitiesOfTypes('TickObject');

test/async-hooks/test-pipeconnectwrap.js

@@ -17,9 +17,9 @@ let pipe1, pipe2;
 let pipeserver;
 let pipeconnect;
 
-net.createServer(common.mustCall(function(c) {
+const server = net.createServer(common.mustCall((c) => {
   c.end();
-  this.close();
+  server.close();
   process.nextTick(maybeOnconnect.bind(null, 'server'));
 })).listen(common.PIPE, common.mustCall(onlisten));
 

test/async-hooks/test-queue-microtask.js

@@ -11,11 +11,11 @@ hooks.enable();
 
 const rootAsyncId = async_hooks.executionAsyncId();
 
-queueMicrotask(common.mustCall(function() {
+queueMicrotask(common.mustCall(() => {
   assert.strictEqual(async_hooks.triggerAsyncId(), rootAsyncId);
 }));
 
-process.on('exit', function() {
+process.on('exit', () => {
   hooks.sanityCheck();
 
   const as = hooks.activitiesOfTypes('Microtask');