[clang] [llvm] [clang][python][test] Move python binding tests to lit framework (PR #142948)

[Rainer Orth via llvm-commits]

rorth wrote:

Two issues are worth mentioning about the updated PR:
- Although I'd originally disabled the Clang Python tests on SPARC in [[python, tests] Disable Clang Python tests on SPARC](https://reviews.llvm.org/D60046), they now `PASS` on Solaris/sparcv9, while on Linux/sparc64 `python` `SEGV`s when loading `libclang.so`.  In a `Debug` build, however, I get a `SIGBUS` which seems to point to an FFI issue again, so I'm restricting the `XFAIL` to Linux/sparc64.
- I'm now logging unhandled failures from `lit.local.cfg` so there's a clear indication what's wrong and where to look.

https://github.com/llvm/llvm-project/pull/142948