[clang] [llvm] [CMake] Add a linker test for -Bsymbolic-functions to AddLLVM (PR #79539)

[Brad Smith via cfe-commits]

brad0 wrote:

> What's the issue? GNU ld has had -Bsymbolic-functions since 2007 and for quite a few releases LLVM has been using `-Bsymbolic-functions`.

This is binutils 2.17. We've had patches for awhile in our tree too specifically for the exceptions not using LLD.

https://github.com/llvm/llvm-project/pull/79539