perf_hooks: make nodeTiming a first-class object

Render all properties of nodeTiming enumerable
so JSON.stringify and Object.keys can access them

Fixes: https://github.com/nodejs/node/issues/35936

PR-URL: https://github.com/nodejs/node/pull/35977


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>