Incorrect move pos detection

I have a case for a list of 10 elements, swapping list[1] and list[8] to each other
```javascript
var tmp = list[1]
list[1] = list[8]
list[8] = tmp
```
Library incorrectly detects everything between 1 and 8 idx as moved and produces 8 MOVE effects, with prev = next for [2-7] elements.
Elements in between has the same indices and it should produce UPDATE for them.