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

[Aaron Ballman via cfe-commits]

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@@ -0,0 +1,4 @@
+// RUN: not %clang -target spirv %s 2>&1 | FileCheck %s
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AaronBallman wrote:

```suggestion
// RUN: not %clang_cc1 -target spirv %s 2>&1 | FileCheck %s
```
Switching to cc1 mode (basically everything but Driver tests should be using cc1).

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