[lld] [libcxx] [openmp] [llvm] [clang] [lto] Add minimum macos sdk requirement to test (PR #77695)

[Florian Hahn via llvm-commits]

fhahn wrote:

Hmmm, did you try this with a newer SDK to confirm it works as expected or is possible that it now just doesn't run?

Do you know what SDK version the failing system has? The option handling is done by `libLTO` built from source, so I'd be surprised if that doesn't get passed through

https://github.com/llvm/llvm-project/pull/77695