[compiler-rt] [Sanitizers][Darwin] Pass offset to __asan_set_shadow_xx (PR #71745)

[Roy Sundahl via llvm-commits]

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

This LGTM. It's the simplest way to get what you want without changing the instrumentation pass to use a constant instead of a variable when -fsanitize-stable-abi is true. We might want to go there in the future though for the performance advantages.

https://github.com/llvm/llvm-project/pull/71745