[clang] [clang] fix broken canonicalization of DeducedTemplateSpecializationType (PR #95202)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

I don't think regression tests are the right level here, we risk creating an unstable test.

I have added a new unittest module for Profiling tests. I hope some day we will have time to add one test case for each property of each AST node.

Though I still think the first line of defense here should have been code review.

https://github.com/llvm/llvm-project/pull/95202