UBSan: undefined behaviours when using `-fsanitize=undefined -fno-sanitize-recover` on free-threaded build

[picnixz]

Bug report

Bug description:

This issue mirrors #111178 but is dedicated to tracking UB failures for the free-threaded build. There should be only two free-threaded-specific issues and the rest are tracked in #132097.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-132399: fix invalid function signatures on the free-threaded build #132400
• gh-132399: ensure correct alignment of PyInterpreterState when UBSan is on #132428

[picnixz]

AFAIK, there is no other UB. I'll re-use that issue if there are more UBs that appear in the future.