* Suppress deprecated function notices in `tests/theme/themeDir.php` 
* Set `$theme['Template Files']` and `$theme['Stylesheet Files']` to a variable before calling array methods upon them - avoids `Indirect modification of overloaded element has no effect` notice
* Clean up setUp/tearDown in `tests/theme.php`

See #25282.



git-svn-id: https://develop.svn.wordpress.org/trunk@25388 602fd350-edb4-49c9-b593-d223f7449a82