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

[Ulrich Weigand via cfe-commits]

uweigand wrote:

Note that I still see the same failure when adding -triple x86_64-unknown-linux-gnu to the first RUN line.

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