Add prefer-iterator-to-array-at-end rule

[nami8824]

Closes #2767

What

Adds a new rule that enforces calling .toArray() at the end of an iterator method chain, rather than in the middle.

Notes

• flatMap is intentionally excluded: Iterator#flatMap requires the callback to return an iterable, while Iterator#flatMap requires the callback to return an iterable, whereas Array#flatMap does not.
• Callbacks with more than 2 parameters are skipped: Array#filter/map passes a third argument (the array itself), but Iterator#filter/map does not.