[clang] [CIR] Make ClangIR compatible with latest nested name specifier AST representation (PR #152846)

[Matheus Izvekov via cfe-commits]

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@@ -120,8 +120,10 @@ static void emitMemberInitializer(CIRGenFunction &cgf,
 
 static bool isInitializerOfDynamicClass(const CXXCtorInitializer *baseInit) {
   const Type *baseType = baseInit->getBaseClass();
-  const auto *baseClassDecl =
-      cast<CXXRecordDecl>(baseType->castAs<RecordType>()->getDecl());
+  const auto *baseClassDecl = cast<CXXRecordDecl>(baseType->castAs<RecordType>()
+                                                      ->getOriginalDecl()
+                                                      ->getDefinitionOrSelf()
+                                                      ->getDefinitionOrSelf());
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mizvekov wrote:

```suggestion
                                                      ->getDefinitionOrSelf());
```

https://github.com/llvm/llvm-project/pull/152846