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

[Ding Fei via cfe-commits]

danix800 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`.

Thanks for reviewing. There's one more other similar crash (with this fix) and I'm still reducing the testcase. I need to dig a  bit more for the cause of the later crash.

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