[clang] [Clang](NFC) Add coverage for VTable debug info (PR #151818)

[Javier Lopez-Gomez via cfe-commits]

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@@ -30,23 +28,26 @@ struct CDerived : NSP_1::CBaseOne, NSP_2::CBaseTwo {
   int six() override { return 66; }
 };
 
+void use(void *, ...);
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jalopezg-git wrote:

(Very minor) nit-pick: add empty line to make it look similar as other test files (e.g. clang/test/DebugInfo/CXX/vtable-inheritance-diamond.cpp).
```suggestion
void use(void *, ...);

```

https://github.com/llvm/llvm-project/pull/151818