Fixes #682 When calling `Row::setCellIndex`, it's possible to create a Row with holes. Instead of iterating over existing cells of a Row, we should instead use the cell indexes (from 0 to max cell index).
Fixes #682 When calling `Row::setCellIndex`, it's possible to create a Row with holes. Instead of iterating over existing cells of a Row, we should instead use the cell indexes (from 0 to max cell index).