[clang] [Clang] Handle consteval expression in array bounds expressions (PR #66222)

[Shafik Yaghmour via cfe-commits]

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@@ -5490,6 +5490,9 @@ TreeTransform<Derived>::TransformDependentSizedArrayType(TypeLocBuilder &TLB,
   EnterExpressionEvaluationContext Unevaluated(
       SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
 
+  // VLA bounds are not truly constant.
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shafik wrote:

This is not always a VLA right? So maybe saying `If we have a VLA then it won't be a constant` 

https://github.com/llvm/llvm-project/pull/66222