[llvm] [GitHub] Add basic CI for libclang Python binding unit tests (PR #76784)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

No further issues on my end. We'll have to carefully monitor the cache usage, but this should be pretty similar to the SPIR-V precommit testing.

@tstellar should take a look at this before landing though.

https://github.com/llvm/llvm-project/pull/76784