[llvm] [llvm] revisions to `LLVM_ABI` export macro definitions (PR #144598)

[Saleem Abdulrasool via llvm-commits]

compnerd wrote:

On windows, the static and dynamic library builds are fundamentally non-substitutable. The build mode impacts the code generation, and so building the library twice to link differently is required. The difference is something that even Linux could stand to benefit from. For the particular case at hand that rebuild is pretty trivial - it is effectively just LLVMSupport.

https://github.com/llvm/llvm-project/pull/144598