[clang] Reapply "[Clang][Sema] Fix crash when 'this' is used in a dependent class scope function template specialization that instantiates to a static member function (#87541)" (PR #88311)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

Can you point out the 'diff' from the last patch for me? 

https://github.com/llvm/llvm-project/pull/88311