[clang] [HLSL] Enable frontend IR generation for SPIR-V in TypedBuffers-constructor.hlsl (PR #207421)

[Diego Novillo via cfe-commits]

================

----------------
dnovillo wrote:

Not sure, unless we globbed some elements, which would weaken the tests. The two outputs differ by more than the prefix. For instance, types are `target("dx. TypedBuffer", float, 1, 0, 0)` vs `target("spirv. Image", float, 5, 2, 0, 0, 2, 3)`. Signed buffers have completely different names. Alignment and calling conventions also differ. 

I tried having similar lines with various `-D` for `FileCheck`. This added a bunch of lines at the top but then the check lines are full of `[[...]]` words.

I think it's a toss-off. Happy to do that, if you prefer that style.

https://github.com/llvm/llvm-project/pull/207421