[META] Remove all usages of drupal_static() & drupal_static_reset()

I agree with waiting until there is a standard replacement for drupal_static() which provides equivalent functionality and can be easily employed to replace the original API calls.

I'm really startled to observe that a lot of commits have been made replacing drupal_static() with plain PHP static! To my mind that is counter-productive and achieves nothing more than the removal of useful functionality.

I think those commits ought to be revisited once a new API is available so that they can be refitted with the new standard.

Per #86, setting this to Postponed pending 🌱 [policy] Standardize how we implement in-memory caches Needs work .

(And once that is resolved, the previous changes made for this issue ought to be reviewed.)