[llvm] llvm-reduce: Don't print verifier failed machine functions (PR #109673)

[Arthur Eubanks via llvm-commits]

https://github.com/aeubanks commented:

what about passing a `raw_ostream&` to the machine verifier that defaults to `errs()`? and we can pass `nulls()` from llvm-reduce

https://github.com/llvm/llvm-project/pull/109673