benchmark: refactor for consistent style

Code in benchmark directory sometimes uses `function () {}` for
anonymous callbacks and sometimes uses `() => {}`. Multi-line arrays
sometimes have a trailing comma and sometimes do not. Update to always
use arrow functions for anonymous callbacks and trailing commas for
multiline arrays.

PR-URL: #25944
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: Trott

benchmark/_cli.js

@@ -6,10 +6,8 @@ const path = require('path');
 // Create an object of all benchmark scripts
 const benchmarks = {};
 fs.readdirSync(__dirname)
-  .filter(function(name) {
-    return fs.statSync(path.resolve(__dirname, name)).isDirectory();
-  })
-  .forEach(function(category) {
+  .filter((name) => fs.statSync(path.resolve(__dirname, name)).isDirectory())
+  .forEach((category) => {
     benchmarks[category] = fs.readdirSync(path.resolve(__dirname, category))
       .filter((filename) => filename[0] !== '.' && filename[0] !== '_');
   });

benchmark/buffers/buffer-bytelength.js

@@ -12,7 +12,7 @@ const chars = [
   'hello brendan!!!', // 1 byte
   'ΰαβγδεζηθικλμνξο', // 2 bytes
   '挰挱挲挳挴挵挶挷挸挹挺挻挼挽挾挿', // 3 bytes
-  '𠜎𠜱𠝹𠱓𠱸𠲖𠳏𠳕𠴕𠵼𠵿𠸎𠸏𠹷𠺝𠺢' // 4 bytes
+  '𠜎𠜱𠝹𠱓𠱸𠲖𠳏𠳕𠴕𠵼𠵿𠸎𠸏𠹷𠺝𠺢', // 4 bytes
 ];
 
 function main({ n, len, encoding }) {
@@ -33,9 +33,7 @@ function main({ n, len, encoding }) {
     }
 
     // Check the result to ensure it is *properly* optimized
-    results = strings.map(function(val) {
-      return Buffer.byteLength(val, encoding);
-    });
+    results = strings.map((val) => Buffer.byteLength(val, encoding));
   }
 
   bench.start();