[compiler-rt] [compiler-rt][builtins] Upstream __isPlatformOrVariantPlatformVersionAtLeast() (PR #100605)

[Louis Dionne via llvm-commits]

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

LGTM -- we can address the documentation requirements as a follow-up since this is essentially upstreaming a downstream diff and it'll make it easier to handle.

https://github.com/llvm/llvm-project/pull/100605