[llvm] [dsymutil] Fix parallel linker's self-recursive typedef DIE (PR #166675)

[Roy Shi via llvm-commits]

royitaqi wrote:

> Could we include the canonical referred-to type in the synthetic name? I.e unwrap the typefed type?

Thanks for the advice. IIUC, that's the "different implementation" mentioned in the description of this patch.

I have just created https://github.com/llvm/llvm-project/pull/166767.   Would love your review there.

https://github.com/llvm/llvm-project/pull/166675