lib: simplify own keys retrieval

This replacement can save us a function call, two array spreadings,
and an array concatenation.

PR-URL: #24582
Refs: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Reflect/ownKeys#Description
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

lib/internal/safe_globals.js

@@ -1,9 +1,7 @@
 'use strict';
 
 const copyProps = (unsafe, safe) => {
-  for (const key of [...Object.getOwnPropertyNames(unsafe),
-                     ...Object.getOwnPropertySymbols(unsafe)
-  ]) {
+  for (const key of Reflect.ownKeys(unsafe)) {
     if (!Object.getOwnPropertyDescriptor(safe, key)) {
       Object.defineProperty(
         safe,