[clang] Reapply "[Clang][Sema] Refactor collection of multi-level template argument lists (#106585, #111173)" (PR #111852)

[kadir çetinkaya via cfe-commits]

kadircet wrote:

i've posted another reduced test case in https://github.com/llvm/llvm-project/pull/114569, as crash bisected to that commit specifically

https://github.com/llvm/llvm-project/pull/111852