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

[Haojian Wu via cfe-commits]

hokein wrote:

This also introduces a regression for modules, see the reproducer https://gist.github.com/hokein/3fa75d75b53aba1671cf0c2bfa64c6f3.

```
Building nest_struct pcm
Building tensor_allocataor_interface pcm
Building main.cc
In module 'tensor_allocator_interface':
./tensor_types.h:89:7: error: 'tensorflow::TTypes<float>::Tensor32Bit' from module 'tensor_allocator_interface.tensor_allocator_interface.h' is not present in definition of 'tensorflow::TTypes<float>' in module 'nest_struct.nest_struct.h'
   89 |       Tensor32Bit;
      |       ^
./tensor_types.h:89:7: note: declaration of 'Tensor32Bit' does not match
   89 |       Tensor32Bit;
      |       ^
1 error generated.
```

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