[3.11] gh-96954: Add tests for unicodedata.name/lookup (GH-96955) (GH-96991)

They were undertested, and since GH-96954 might involve a
rewrite of this part of the code we want to ensure that
there won't be any behavioral change.

Co-authored-by: Carl Friedrich Bolz-Tereick <cfbolz@gmx.de>
(cherry picked from commit 5a32eeced2c537c13613dd4ff5b2767a37037294)

Co-authored-by: Batuhan Taskaya <isidentical@gmail.com>