benchmark: add MessagePort benchmark

Add a raw `MessagePort` benchmark that does not ping back and forth
between different threads, unlike the `echo.js` benchmark, as there
are some performance differences between single-threaded and multi-
threaded operation, and a single-threaded Environment can be somewhat
easier to work with when profiling.
PR-URL: #31568
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

Author: addaleax

benchmark/worker/messageport.js

@@ -0,0 +1,42 @@
+'use strict';
+
+constcommon=require('../common.js');
+const{ MessageChannel }=require('worker_threads');
+constbench=common.createBenchmark(main,{
+payload: ['string','object'],
+n: [1e6]
+});
+
+functionmain(conf){
+constn=conf.n;
+letpayload;
+
+switch(conf.payload){
+case'string':
+payload='hello world!';
+break;
+case'object':
+payload={action: 'pewpewpew',powerLevel: 9001};
+break;
+default:
+thrownewError('Unsupported payload type');
+}
+
+const{ port1, port2 }=newMessageChannel();
+
+letmessages=0;
+port2.onmessage=()=>{
+if(messages++===n){
+bench.end(n);
+port1.close();
+}else{
+write();
+}
+};
+bench.start();
+write();
+
+functionwrite(){
+port1.postMessage(payload);
+}
+}