Fix `Tests_Paginate_Links` tests by properly setting up / tearing down permalink structure.

Props jorbin.
Fixes #29636.


git-svn-id: https://develop.svn.wordpress.org/trunk@29913 602fd350-edb4-49c9-b593-d223f7449a82
Add a 6th (!) attribute to `wp_get_attachment_link()` to allow `aria-describedby` to be added to gallery output.

Props joedolson, DrewAPicture, rianrietveld.
Fixes #27402.


git-svn-id: https://develop.svn.wordpress.org/trunk@29914 602fd350-edb4-49c9-b593-d223f7449a82
Cache `get_term_by()` calls:

* Add a helper function, `wp_get_last_changed()`, to retrieve a last-modified timestamp by cache group
* When caching a term, also make cache entries for slug and name via `slug:{$term_id}` and `name:{$term_id}` keys in the `$taxonomy:$last_changed` bucket that reference the term_id
* In `clean_term_cache()` and `update_term_cache()`, respect `$_wp_suspend_cache_invalidation`
* Original term cache entries maintain BC

Adds unit tests.

Props wonderboymusic, tollmanz, boonebgorges.
Fixes #21760.


git-svn-id: https://develop.svn.wordpress.org/trunk@29915 602fd350-edb4-49c9-b593-d223f7449a82
Split and organize multisite unit tests

* Move `ms.php` to `multisite.php`
* Create `multisite.php` under directories `option/` and `user/` to better match existing structure.
* Create a `multisite/` directory containing `bootstrap.php`, `site.php`, and `network.php` for very multisite specific testing.
* Add unit test groups ms-site, ms-user, ms-option, ms-network, and ms-bootstrap.

Fixes #29896


git-svn-id: https://develop.svn.wordpress.org/trunk@29916 602fd350-edb4-49c9-b593-d223f7449a82