Exception raised on the construction of the tensor from the `tensor_expression`

When constructing expression such as `A + 3 * B` and constructing a tensor out of the expression, the exception is raised, which should not happen.

```cpp
using tensor_t = tensor_dynamic;
auto const e = extents<>{3,2};

auto const a = tensor_t(e, 1.f);

auto const three = 3.f;
auto const expr = a + three * a;
auto const t = tensor_t(expr); // exception
```