expect callableNotToThrow does not modify assertion count

When testing that an exception is not thrown, the assertion count is not raised. This is true for both variants on the latest 2.2 release:

```php
verify($callable)->callableDoesNotThrow(\Exception::class);
expect($callable)->callableNotToThrow(\Exception::class);
```

Here is a sample test:

```php
public function testCallableDoesNotThrow()
{
$testFunction = function() {};
expect($testFunction)->callableNotToThrow(\Exception::class);
}
```