benchmark: (os) use destructuring

PR-URL: #18250
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: James M Snell <[email protected]>

Author: BridgeAR

benchmark/os/cpus.js

@@ -7,9 +7,7 @@ const bench = common.createBenchmark(main, {
   n: [3e4]
 });
 
-function main(conf) {
-  const n = +conf.n;
-
+function main({ n }) {
   bench.start();
   for (var i = 0; i < n; ++i)
     cpus();

benchmark/os/loadavg.js

@@ -7,9 +7,7 @@ const bench = common.createBenchmark(main, {
   n: [5e6]
 });
 
-function main(conf) {
-  const n = +conf.n;
-
+function main({ n }) {
   bench.start();
   for (var i = 0; i < n; ++i)
     loadavg();