[clang] Reapply "[analyzer] Fix false positive in strchr/strrchr with constant args" (PR #212124)

[Balázs Benics via cfe-commits]

steakhal wrote:

> This is still failing on s390x-linux as well. Looks like some host endian issues, maybe?

If both RUN lines pin the target triple, how does it matter what host we are executing the tests on?

https://github.com/llvm/llvm-project/pull/212124