[llvm] [NFC][SLU] Update SimpleLoopUnswitch/guards.ll (PR #166285)

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

Could you please regenerate checks by dropping `-p` from UTC_ARGS? I don't think it's particularly useful here, and this way, latest UTC version checks are employed.

https://github.com/llvm/llvm-project/pull/166285