[clang] [Clang] diagnosing missing Vulkan environment when using SPIR-V triple (PR #190840)

[Tony Guillot via cfe-commits]

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to268 wrote:

I think you should take inspiration from [hlsl-lang-targets-spirv.hlsl](https://github.com/llvm/llvm-project/blob/main/clang/test/Driver/hlsl-lang-targets-spirv.hlsl) to write your test and make it pass pre-commit CI checks.

https://github.com/llvm/llvm-project/pull/190840