lib: fix nits in lib/internal/bootstrap/cache.js

* Unwrap short lines.
* Unify comments.
* Decrease function calls.

PR-URL: https://github.com/nodejs/node/pull/24581


Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>