[clang] [compiler-rt] [libcxx] [libunwind] [llvm] [openmp] [cmake] switch to CMake's native `check_{compiler,linker}_flag` (PR #96171)

[via llvm-commits]

h-vetinari wrote:

> It seems that the Android support in the Dockerfile is broken after a refactor last year. I have some changes that get it working again.

 I was waiting for your recent PRs to land, but the android failures seem to persist even after them.

https://github.com/llvm/llvm-project/pull/96171