Clang doesn't generate a function when using __array_rank

The code [(Godbolt)](https://godbolt.org/z/3qe4Gqqvx)
```c++
#include <__type_traits/integral_constant.h>

template <class T>
struct rank : std::integral_constant<int, __array_rank(T)> {};

template <class T>
void test_rank() {
  static_assert(rank<T>::value == 0);
}

void func() {
  test_rank<void>();
}
```
generates `func()`, but doesn't generate `test_rank<void>()`.
