Make tests for warnings in the re module more strict

[serhiy-storchaka]

#122357 passed existing tests because tests for warnings in the re module only tested re.compile() and did not test stack level.

Linked PRs

• gh-122798: Make tests for warnings in the re module more strict #122799
• [3.13] gh-122798: Make tests for warnings in the re module more strict (GH-122799) #122804
• [3.12] gh-122798: Make tests for warnings in the re module more strict (GH-122799) #122805