[clang] [clang][AST] CXXRecords in anony namespace from diff TUs shouldn't be equivalent (PR #112534)

[Balázs Kéri via cfe-commits]

balazske wrote:

The fix looks acceptable, but a test is needed. The test code in the bug report can be used somehow in at the AST merge LIT tests or in the `ASTImporterTest`.

https://github.com/llvm/llvm-project/pull/112534