iterators3 IntegerOverflow test too easy

[deafloo]

The test only checks for divide(i64::MIN, -1). In my solution, I just raised an IntegerOverflow Error every time the divisor was -1 and the exercise passed.
I would suggest adding more positive checks e.g. divide(10, -1), Ok(-10) and divide(i64::MIN, i64::MIN), OK(1) to close this shortcut!