Experiment with removing the static cache from filecache

Problem/Motivation

The default file implementation uses APCu.

There is 📌 Add a core FileCache implementation that is database-backed Active but it also uses APCu.

However FileCache implements a static cache on top of these. I think we can 1. leave this to the implementations to handle 2. not bother when apcu is in use in the implementation to try to save some memory usage for situations like drush.

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet