lib,src: make constants not inherit from Object

Make sure `constants` object and all the nested objects don't inherit
from `Object.prototype` but from `null`.

PR-URL: https://github.com/nodejs/node/pull/10458


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Brian White <mscdex@mscdex.net>