Revert test for Tix deprecation warning (GH-26005)

Added in bpo-41730 (GH-22186), the test apparently causes refleaks.  The
test isn't worth hunting them down, so it's simply reverted.

This partially reverts commit 4a2d98a1e98de25c5114d11fcb0f9fedbb057e51.
(cherry picked from commit 8e8307d70bb9dc18cfeeed3277c076309b27515e)

Co-authored-by: Zachary Ware <zach@python.org>