lib: refactor policy code for readability

Simplify a few particularly quirky bits of code, and add
whitespace for readability.

PR-URL: https://github.com/nodejs/node/pull/25629


Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>