[compiler-rt] Make SANITIZER_MIN_OSX_VERSION a cache variable (PR #74394)

[Vitaly Buka via llvm-commits]

https://github.com/vitalybuka approved this pull request.

LGTM but please wait a few days for others feedback

@petrhosek For CMAKE expertise 

@yln @sundahl as it impacts OSX

https://github.com/llvm/llvm-project/pull/74394