[libcxx] [llvm] [libc++] Add a new job running the CFI sanitizer (PR #124837)

[Nikolas Klauser via llvm-commits]

philnik777 wrote:

The CFI documentation says that you need LTO, so we probably have to explicitly enable that as well and use lld (since bfd doesn't support LTO)

https://github.com/llvm/llvm-project/pull/124837