[flang] [llvm] Reland [VPlan] Expand WidenInt inductions with nuw/nsw (PR #168354)

[Danila Malyutin via llvm-commits]

danilaml wrote:

@artagnon we also see miscompiles after this on some internal fuzzing tests (507f236 didn't help). I'll try to extract some minimal reproducer.

https://github.com/llvm/llvm-project/pull/168354