[3.13] gh-136442: Fix unittest to return exit code 5 when setUpClass raises an exception (GH-136487) (#141577)

gh-136442: Fix unittest to return exit code 5 when setUpClass raises an exception (GH-136487)
(cherry picked from commit 53d65c840e038ce9a5782fbd3da963c7aba90570)

Co-authored-by: Takuya UESHIN <ueshin@happy-camper.st>