[llvm] [Local] Move OverflowTracking to Local.h, move logic to helpers (NFC) (PR #140403)

[Philip Reames via llvm-commits]

https://github.com/preames approved this pull request.

LGTM

I'll note that leaving the AllKnownNonZero in Reasociate seems slightly odd, but we can be incremental here.  

https://github.com/llvm/llvm-project/pull/140403