[llvm] [NVPTX] Fix lowering of i1 SETCC (PR #115035)

[Artem Belevich via llvm-commits]

Artem-B wrote:

How much of a difference would it make on the SASS level if we were to just extend i1 arguments to i32 and then just run `setp` on them, instead of logical ops done directly on predicates? 

E.g. setp.lt(i1 a, i1 b) -> `setp.lt(i32 selp(a, 1, 0), i32 selp(b(1,0)))`

https://github.com/llvm/llvm-project/pull/115035