[clang] [llvm] [clang] Remove shell requirements from tests (PR #156905)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

> Probably confirm w Petr and Reid before landing though.

We discussed this offline and the consensus was that `symlinks` should be a top level feature and it's fine to just disable them on Windows, which is what this patch ended up doing. Given that I'm going to land this and if there's any further commentary I can follow up afterwards.

https://github.com/llvm/llvm-project/pull/156905