Replace `.toSorted`, `.toSpliced`, `.toReversed` with `.clone`

This is the same reasoning behind why I'd like to add JSON.equals(x, y) as an internalized synonym for JSON.stringify(x) === JSON.stringify(y) - if the two JSON trees are walked simultaneously, the engine doesn't have to do as much work or allocate as much memory. (Not to mention it offers an obvious fast-path escape hatch if x === y)