[clang] [analyzer] TaintPropagation checker strlen() should not propagate (PR #66086)

[Balazs Benics via cfe-commits]

steakhal wrote:

I actually wanted to propose another patch where the wchar variant of strlen would propagate taint, BTW. I still plan to do it, we will see when I reach that.

https://github.com/llvm/llvm-project/pull/66086