Introduced along with the `did_filter()` function, the `$wp_filters` global stores the number of times each filter has been applied during the current request.
This commit adds `$wp_filters` to the list of globals that are saved in `WP_UnitTestCase_Base::_backup_hooks()` and restored in `::_restore_hooks()` so that hooks set by the current test do not accidentally affect future tests.
Additionally, this commit brings some consistency by backing up and restoring the hook-related globals in the same order they are defined in `wp-includes/plugin.php`.
Follow-up to [29251], [53803].
Props sanjucta, SergeyBiryukov.
Fixes#57236.
git-svn-id: https://develop.svn.wordpress.org/trunk@55160 602fd350-edb4-49c9-b593-d223f7449a82