Invalid strides type for static extents of rank one

Right now, the static tensor gets confused about which strides type it should use for rank one extents because of the ambiguity between the `extents_static_rank<4>` and `extents_static<4>`. This ambiguity occurs because, behind the scene, they both are the specialization of the `extents_core<...>`.

When we create a static tensor of rank one, instead of choosing the strides from the `extents_static`, it chooses the strides from the `extents_static_rank`.

```cpp
auto t = tensor_static>(); // error: no viable conversion from 'const array<[...], 1>' to 'const array<[...], 2UL aka 2>'
```