[clang] [Sema] do not destruct fields of unions (PR #122330)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Thank you for the fix! The changes look correct to me, but I added the CFG and Analysis maintainers to give a final sign-off. Can you also add something to `clang/docs/ReleaseNotes.rst` so users know about the fix?

https://github.com/llvm/llvm-project/pull/122330