ArrayData Equality Slice Iterator

[tustvold]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

A lot of the ArrayData equality implementation iterate through row-wise in the event of nulls, it would be advantageous to instead iterate over valid ranges, for example, using SlicesIterator. I originally planned to do this as part of #1589 but that PR already is rather large so creating as ticket and will follow up later

Describe the solution you'd like

Should use SlicesIterator to amortize the cost of performing equality comparisons