[clang] [C++20] [Modules] Don't check redeclaration for TagUseKind::Referencekind declaration (PR #194546)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

Given how simple the patch is (so that it is simple to revert too), I want to land this 1 month later if no more comments came in

https://github.com/llvm/llvm-project/pull/194546