[clang] [clang] Update Mach-O ptrauth driver defaults (PR #132834)

[Jon Roelofs via cfe-commits]

jroelofs wrote:

Looks mechanically okay, but I need to defer to Ahmed on whether you're missing other bits that go along with this. He's around, just need to be patient ;)

https://github.com/llvm/llvm-project/pull/132834