[clang] [HLSL] standardize builtin unit tests (PR #83340)

[Farzon Lotfi via cfe-commits]

farzonl wrote:

> Do we have the suggestions that this is responding to written down somewhere? I think it would be useful to have those guidelines for anyone who might want to contribute HLSL tests. At any rate, I'd like to know the ones that this is in response to.

After consulting with some folks. clang format in this case is just going to be a one off. It doesn't make sense to have different contribution guidelines from the rest of clang. There are times we want the formatting to be off. These tests aren't one of those cases.

https://github.com/llvm/llvm-project/pull/83340