[clang] Reapply "[Clang][Sema] Refactor collection of multi-level template argument lists (#106585)" (PR #111173)

[Krystian Stasiowski via cfe-commits]

sdkrystian wrote:

> Do you think you'll have a fix within a couple of hours

@mstorsjo I think so. If not, I'll revert.

https://github.com/llvm/llvm-project/pull/111173