The following code:
```
# cython: infer_types=True
import cython

@cython.cclass
class Foo:
    a: cython.double
    b: cython.double
    c: cython.double

    def __init__(self, a: cython.double, b: cython.double ,c: cython.double):
        self.a = a
        self.b = b
        self.c = c

def bar():
    l = []
    l.append(Foo(10, 20, 30))

    v = cython.declare(Foo, l[0])
    r = v.a + v.b
    print( r )

    v2 = cython.cast(Foo, l[0]) #Faster - No __Pyx_TypeTest() call
    r = v2.b + v2.c
    print( r )

bar()
```
works fine when compiled and throws an exception when interpreted: `TypeError: __init__() missing 2 required positional arguments: 'b' and 'c'`

It could be fixed if we change implementations as shown in the patch.
Also, added more tests for the cases I'm trying to fix
NB: Removed execution of `test_declare(None)` to make sure that the new `none_declare()` test works instead. `test_declare(None)` doesn't throw exception in pure mode but does it in the native mode

Replacing `hasattr(t, '__call__')` to `callable(t)` in the master branch broke the implementation and the tests because the construction was used to detect typedefs. To fix that I got rid of this check completely and replaced it to exact checks which also simplified the code

Changed `declare` implementation when initializing arguments are not provided. Now it correctly works with typedefs of the user classes and also directly support arrays:
    ```
    >>> EmptyClassSyn = cython.typedef(EmptyClass)
    >>> cython.declare(EmptyClassSyn) is None
    True
    >>> cython.declare(cython.int[2]) is not None
    True
    ```
Added missed return statement to `index_type` which made the following assigment possible:
    ```
        a = cython.declare(cython.int[2])
        a[0] = 1
    ```