[libclc] [llvm] [libclc] Replace llvm-dis with llvm-nm in check-external-funcs.test (PR #187190)

[Matt Arsenault via cfe-commits]

arsenm wrote:

> It doesn't require a script and also works on windows.

You could fully implement this in cmake without depending on bash 




https://github.com/llvm/llvm-project/pull/187190