Prior to 4.7, term relationships - as set by `wp_set_object_terms()` or
`wp_remove_object_terms()` - did not affect the term query cache. The
introduction of the 'object_ids' parameter in 4.7 means that the query
cache must be aware of object-term relationships. As such, the
'last_changed' incrementor is now invalidated when term relationships
are modified.
This bug only reared its head when delaying term counting, because term
counting performs its own term query cache invalidation.
Props mboynes.
Fixes#40306.
git-svn-id: https://develop.svn.wordpress.org/trunk@40353 602fd350-edb4-49c9-b593-d223f7449a82
cc1c0639d0