[llvm] [JITLink][AArch32] Add explicit visibility macros to functions needed by unittests (PR #116557)

[Stefan Gränitz via llvm-commits]

weliveindetail wrote:

Thanks for bringing this up. These functions were never meant to be exported publically, we only want to access them for testing. Does that make a difference for the LLVM_ABI tag? Do we have similar situations anywhere else in the codebase?

In order to avoid confusion, we could also make a local LLVM_TEST_ABI redefinition with with a note. Or if this only affects Windows, we could disable the respective unittets there. What do you think?

https://github.com/llvm/llvm-project/pull/116557