[clang] [clang] [sanitizer] predict trap checks succeed (PR #134310)

[Florian Mayer via cfe-commits]

fmayer wrote:

> Last time I checks, if the branch endup with unreachable, compiler can figure it out as UNLIKELY. So PR like this is effectively NOP.

I built tcmalloc with and without this change and get different codegen

https://github.com/llvm/llvm-project/pull/134310