Modernize benchmarks (#2132)

* Introduce benchmarks

tasks/metrics.js

@@ -1,29 +0,0 @@
-const metrics = require('../tests/bench');
-const { createRegisterAsyncTaskFn } = require('./util/async-grunt-task');
-
-module.exports = function (grunt) {
-  const registerAsyncTask = createRegisterAsyncTaskFn(grunt);
-
-  registerAsyncTask('metrics', function () {
-    const onlyExecuteName = grunt.option('name');
-    const events = {};
-
-    const promises = Object.keys(metrics).map(async (name) => {
-      if (name.startsWith('_')) {
-        return;
-      }
-      if (onlyExecuteName != null && name !== onlyExecuteName) {
-        return;
-      }
-
-      return new Promise((resolve) => {
-        metrics[name](grunt, function (data) {
-          events[name] = data;
-          resolve();
-        });
-      });
-    });
-
-    return Promise.all(promises);
-  });
-};