[llvm] [LLVM][CMake][MSVC] Install PDBs alongside executables (PR #120683)

[Alexandre Ganea via llvm-commits]

aganea wrote:

I think the reason why we weren’t doing it before is a concern of installation size. I agree having the PDBs would be useful. I’d rather prefer publishing them on a symbol server, and pull them on-demand instead.

https://github.com/llvm/llvm-project/pull/120683