[clang] [clang-tools-extra] [Clang] Add a builtin that deduplicate types into a pack (PR #106730)

[Ilya Biryukov via cfe-commits]

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@@ -1,5 +1,4 @@
 // RUN: %clang_cc1 -fsyntax-only -std=c++11 %s
-// XFAIL: asserts
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ilya-biryukov wrote:

Yes, I managed to hit a similar case in the new testsuite and fixing it also fixed the corresponding assertion.

I was going to follow up with checking all examples from #100095 before writing the release note in a follow-up after this change lands.

https://github.com/llvm/llvm-project/pull/106730