[clang] [clang] fix uniquing of some TagTypes created from the injected class name (PR #155347)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

I don't think that helps, however the patch is a bit simple, so you could maybe sort of reverse engineer what could have gone wrong from it.

For example, before this patch we would have produced non-identical CXXRecordTypes from basically the same information.  
There is probably somewhere you are comparing non-canonical RecordTypes and now after this patch they are equal.


https://github.com/llvm/llvm-project/pull/155347