[clang] [clang][python][test] Check if libclang.so is loadable (PR #142353)

[Vlad Serebrennikov via cfe-commits]

https://github.com/Endilll commented:

Thank you for the PR. Several points:
1) What happens on Windows?
2) `check-clang-python` is just one of the ways to run into this. `cindex.py` is a user-facing interface, so we shouldn't emit messages that make sense only during development.
3) The fact that `OSError` already contains the message that indicates the problem, I think we should explore why it's not properly emitted in the first place, before introducing bespoke ways of delivering error messages. @DeinAlptraum any thoughts here?

https://github.com/llvm/llvm-project/pull/142353