[clang] [compiler-rt] [Clang] Adjust pointer-overflow sanitizer for N3322 (PR #120719)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic approved this pull request.

LGTM

I don't see any reason to mess with the runtime bits: we try to keep them stable where we can.

https://github.com/llvm/llvm-project/pull/120719