[34529] introduced lazyloading for the metadata belonging to terms matching
posts in the main `WP_Query`. The current changeset improves this technique
in the following ways:
* Term meta lazyloading is now performed on the results of all `WP_Query` queries, not just the main query.
* Fewer global variable touches and greater encapsulation.
* The logic for looping through posts to identify terms is now only performed once per `WP_Query`.
Props dlh, boonebgorges.
See #34047.
git-svn-id: https://develop.svn.wordpress.org/trunk@34704 602fd350-edb4-49c9-b593-d223f7449a82
e75f2c024f