SI-8932 Fix dropRight/takeRight implementations

I looked up at all the overrides of `IterableLike#takeRight` and
`IterableLike#dropRight` and replaced usages of its argument `n` with
`math.max(n, 0)` every time it was being used in an index subtraction.

Fixes [SI-8932](https://issues.scala-lang.org/browse/SI-8932).