test: favor arrow function in callback

PR-URL: #24542
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Author: kotAPI

test/parallel/test-zlib-close-after-write.js

@@ -23,7 +23,7 @@
 const common = require('../common');
 const zlib = require('zlib');
 
-zlib.gzip('hello', common.mustCall(function(err, out) {
+zlib.gzip('hello', common.mustCall((err, out) => {
   const unzip = zlib.createGunzip();
   unzip.write(out);
   unzip.close(common.mustCall());