[clang] [llvm] [clang][python][test] Move python binding tests to lit framework (PR #145855)

[Rainer Orth via cfe-commits]

rorth wrote:

With the exception of `llvm-clang-win-x-armv7l` (another cross build), the remaining failures seem all to be `XPASS`es on AArch64.  I guess it's time to just remove `aarch64` from the `XFAIL` in `bindings.sh` then, something that would never have been noticed with the old `RUN_PYTHON_TESTS` approach where the test would have remained disabled permanently.  I've augmented my patch locally, but will wait if anything else comes up before pushing.

https://github.com/llvm/llvm-project/pull/145855