path: replace "magic" numbers by readable constants

PR-URL: https://github.com/nodejs/node/pull/18654


Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Kyle Farnung <kfarnung@microsoft.com>
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>