[llvm] [llvm] export private symbols needed by unittests (PR #145767)

[Andrew Rogers via llvm-commits]

andrurogerz wrote:

@compnert @vgvassilev after discussion on #145448, I think this approach is better. It is a small number of private symbols needing to be exported for these unit tests. The individual commits show which symbols were required for each test.

https://github.com/llvm/llvm-project/pull/145767