Remove skipped tests for `WP_Export_Query`.

These tests have been added as a patch to the ticket where the new
functionality was originally proposed, #22435.

See #30284.
Built from https://develop.svn.wordpress.org/trunk@30518


git-svn-id: http://core.svn.wordpress.org/trunk@30507 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove failing test in the `hooks` group.

The removed test has been added as a patch to #21169.

Props MikeHansenMe.
See #30284.
Built from https://develop.svn.wordpress.org/trunk@30519


git-svn-id: http://core.svn.wordpress.org/trunk@30508 1a063a9b-81f0-0310-95a4-ce76da25c4cd