[clang] [Clang][Sema] fix crash of attribute transform (PR #78088)

[via cfe-commits]

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@@ -7083,8 +7087,9 @@ QualType TreeTransform<Derived>::TransformAttributedType(
       modifiedType != oldType->getModifiedType()) {
     // TODO: this is really lame; we should really be rebuilding the
     // equivalent type from first principles.
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cor3ntin wrote:

This comment would no longer apply, would it?

https://github.com/llvm/llvm-project/pull/78088