[clang] scan-build-py: respect LLVM_LIBDIR_SUFFIX like other tools do (PR #108549)

[Martin 'JaMa' Jansa via cfe-commits]

shr-project wrote:

> It looks like you're trying to undo #106612? cc @mgorny

Ah, not intentionally, I should have checked the git history more carefully before creating this PR (which is still only a draft). I don't use libscanbuild at all, but in OpenEmbedded builds the python modules are installed in the configured libdir which could be /usr/lib, /usr/lib32, /usr/lib64 and then they are packaged correctly, while libscanbuild didn't follow this and caused installed-vs-shipped QA issue (which basically means that something was installed in locations which aren't packaged by configured rules).

I believe the python code should be fixed to look in the right install locations, but I'll leave that to someone actually using libscanbuild.

https://github.com/llvm/llvm-project/pull/108549