[clang] Reapply "[Clang][Sema] Always use latest redeclaration of primary template" (PR #114569)

[Krystian Stasiowski via cfe-commits]

sdkrystian wrote:

Great! Hopefully this will be the last PR needed to finally get #106585 working :)

https://github.com/llvm/llvm-project/pull/114569