[llvm] [llvm] compile out LLVM_ABI unless building as a shared lib or dylib (PR #134958)

[Thomas Fransham via llvm-commits]

fsfod wrote:

I think i was trying to preserve that symbols for static builds are exported from executables so plugins can us them on Linux. I think i had already converted some existing visibility macro use over to LLVM_ABI.

https://github.com/llvm/llvm-project/pull/134958