Remove a cache-busting hack from `Tests_Term_getTerms::test_get_terms_exclude_tree()`. It is no longer necessary after #14485 and #25711.

See [27300].
Props SergeyBiryukov.
Fixes #27313.



git-svn-id: https://develop.svn.wordpress.org/trunk@27459 602fd350-edb4-49c9-b593-d223f7449a82