[clang] [HLSL] Simplify test (PR #165743)

[Justin Bogner via cfe-commits]

bogner wrote:

On further inspection, we do emit -S from `clang-dxc -fcgl`, and the previous issue was about us emitting it both before and after the -emit-llvm flag. I can see how checking for this would be pretty awkward, and honestly I can't really see how we would end up regressing on this particular issue. I think the test as is looks correct and we should merge this as is.

Thanks for digging into this.

https://github.com/llvm/llvm-project/pull/165743