[clang] [analyzer] Make it a noop when initializing a field of empty record (PR #138594)

[via cfe-commits]

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@@ -715,7 +716,11 @@ void ExprEngine::handleConstructor(const Expr *E,
         // actually make things worse. Placement new makes this tricky as well,
         // since it's then possible to be initializing one part of a multi-
         // dimensional array.
-        State = State->bindDefaultZero(Target, LCtx);
+        const CXXRecordDecl *TargetHeldRecord =
+            cast<CXXRecordDecl>(CE->getType()->getAsRecordDecl());
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isuckatcs wrote:

This cast can actually fail. See the broken testcase:
```
llvm-project/llvm/include/llvm/Support/Casting.h:109: static bool llvm::isa_impl_cl<To, const From*>::doit(const From*) [with To = clang::CXXRecordDecl; From = clang::RecordDecl]: Assertion `Val && "isa<> used on a null pointer"' failed.
```

https://github.com/llvm/llvm-project/pull/138594