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

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

CC @llvm/infrastructure-area-team -- I'm not certain who is the best person to review `lit` work; that's sort of the confluence between infraustructure and the rest of the project. Do you have any good suggestions? (We don't have a maintainer listed for it that I could find.)

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