REST API: Introduce Autosaves controller and endpoint.
- Adds
WP_REST_Autosaves_Controller which extends WP_REST_Revisions_Controller.
- Autosaves endpoint is registered for all post types except attachment because even post types without revisions enabled are expected to autosave.
- Because setting the
DOING_AUTOSAVE constant pollutes the test suite, autosaves tests are run last. We may want to improve upon this later.
Also, use a truly impossibly high number in User Controller tests. The number 100, (or 7777 in trunk), could be valid in certain test run configurations. The REST_TESTS_IMPOSSIBLY_HIGH_NUMBER constant is impossibly high for this very reason.
Finally, Skip Autosaves controller test for multisite. There's a PHP 5.2 edge case where paths calculated differently, possibly caused by differing version of PHPUnit.
Props adamsilverstein, aduth, azaozz, danielbachhuber, rmccue, danielbachhuber.
Merges [43767], [43768], [43769] to trunk.
See #45132, #45131.
Fixes #45128, #43316.