[clang] [libclang/python] Ignore our own DeprecationWarnings in CMake targets (PR #178631)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

I guess I should've mentioned that my while my solution (`catch_warnings`) is on case-by-case basis, it doesn't ensure that the warning was actually emitted. Maybe we can achieve this using a try-catch block?

https://github.com/llvm/llvm-project/pull/178631