[clang] Wrong class specialization is selected when alias template is used for template template parameter

The second static assert in the following trivial example code fails due to incorrect class specialization being selected:
```C++
template class, class>
struct match_class_specialization
{
enum { matches = 0 };
};

template class Type, typename... Ts>
struct match_class_specialization>
{
enum { matches = 1 };
};

template struct my_type {};

static_assert(match_class_specialization>{}.matches);

template using my_type_alias = my_type;

static_assert(match_class_specialization>{}.matches);

int main() {}
```
This compiles fine in GCC.

Start with the minimal C++ reproducer in the issue and compile it with Clang, then compare the result with GCC. Trace the template-template-parameter and alias-template specialization selection involved in the failing second static assertion; done means the alias-template case selects the matching specialization and the assertion passes.

Written by the indexing model from the issue text.