[llvm] [LAA] Clean up APInt-overflow related code (NFC) (PR #140048)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

I thought about this PR some more, and I don't think the tests add value: I've dropped the tests, and this should be a pure NFC cleanup now.

https://github.com/llvm/llvm-project/pull/140048