[compiler-rt] [compiler-rt] Fix interceptors with BTI and PAC (PR #84061)

[Evgenii Stepanov via llvm-commits]

eugenis wrote:

It has to be `BTI C`, AFAIK. PACIASP will sign LR, which I believe will break when the callee will try to sign it again.

https://github.com/llvm/llvm-project/pull/84061