[llvm] Use `ccache-swig` if `ccache` cannot be found (PR #90624)

[Tobias Hieta via llvm-commits]

tru wrote:

I don't this we should add more stuff to LLVM_ENABLE_CCACHE. I think people should use CMAKE_C/CXX_COMPILER_LAUNCHER instead. 

https://github.com/llvm/llvm-project/pull/90624