[clang] [clang][driver][darwin] Prefer DarwinSDKInfo for platform identification and compatibility over the -isysroot path (PR #176541)

[Florian Mayer via cfe-commits]

fmayer wrote:

I think this fails on the ASan bot with a use-after-scope: https://lab.llvm.org/buildbot/#/builders/52/builds/14660/steps/12/logs/stdio

https://github.com/llvm/llvm-project/pull/176541