benchmark: remove deprecated _extend from benchmark

Signed-off-by: RafaelGSS <rafael.nunu@hotmail.com>
PR-URL: https://github.com/nodejs/node/pull/59228
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Ulises Gascón <ulisesgascongonzalez@gmail.com>

benchmark/es/spread-assign.js

@@ -1,42 +0,0 @@
-'use strict';
-
-const common = require('../common.js');
-const util = require('util');
-
-const bench = common.createBenchmark(main, {
-  method: ['spread', 'assign', '_extend'],
-  count: [5, 10, 20],
-  n: [1e6],
-});
-
-function main({ n, context, count, rest, method }) {
-
-  const src = {};
-  for (let n = 0; n < count; n++)
-    src[`p${n}`] = n;
-
-  let obj;
-
-  switch (method) {
-    case '_extend':
-      bench.start();
-      for (let i = 0; i < n; i++)
-        obj = util._extend({}, src);
-      bench.end(n);
-      break;
-    case 'assign':
-      bench.start();
-      for (let i = 0; i < n; i++)
-        obj = Object.assign({}, src);
-      bench.end(n);
-      break;
-    case 'spread':
-      bench.start();
-      for (let i = 0; i < n; i++)
-        obj = { ...src }; // eslint-disable-line no-unused-vars
-      bench.end(n);
-      break;
-    default:
-      throw new Error('Unexpected method');
-  }
-}