[llvm] [llvm][CMake] Fix llvm shared library when using ninja multi config (PR #65451)

[via llvm-commits]

ur4t wrote:

@mgorny It seems that the most recently modification on `llvm/tools/llvm-shlib/CMakeLists.txt` is performed by you. Would you like to participate in reviewing this PR?


https://github.com/llvm/llvm-project/pull/65451