[llvm] [InstCombine] Avoid folding `select(umin(X, Y), X)` with min/max values in false arm (PR #143020)

[Konstantin Bogdanov via llvm-commits]

thevar1able wrote:

@nikic No, it did not. I didn't realize at first that update_test_checks.py was picking up my `opt-19` from system. Later `ninja -C build check-llvm` had failed assertions to find `vector body` section.

https://github.com/llvm/llvm-project/pull/143020