Redundant nesting of StarredElement in Starred with native parser on some cases

Short reproducer:
```py
a, *b
```

Native parser represents `*b` like this:
```py
Element(
  value=StarredElement(
    value=Name(
      value='b',
    ),
  ),
),
```
But the python version represents it in a flat fashion:
```py
StarredElement(
  value=Name(
    value='b',
  ),
),
```