[compiler-rt] [llvm] [RISC-V][Zicfiss] Move shadow stack ops to save/restore builtins (PR #222850)

[Nemanja Ivanovic via llvm-commits]

nemanjai wrote:

> In the meantime: if this combination is known to be broken, can we either ignore -msave-restore (at least the restore path) with a big warning or make it an error? I don't think we should continue silently miscompiling this now that we know it's broken, and shouldn't have to wait on a proper solution before making what we have "work".

I will leave this PR open and post another one to ignore and diagnose the combination.

https://github.com/llvm/llvm-project/pull/222850