Add Change Array by Copy methods

[Samathingamajig]

"Change Array by Copy" is a stage 4 proposal, which means it's ready to come out in the next edition of the ECMAScript standard and is in the current draft. It brings along four new methods for Array.prototype:

• Array.prototype.toReversed() -> Array, returns a reversed version of a shallow copy of the array, leaving the original array intact
• Array.prototype.toSorted(compareFn) -> Array, returns a sorted version of a shallow copy of the array, leaving the original array intact
• Array.prototype.toSpliced(start, deleteCount, ...items) -> Array, returns a spliced version of a shallow copy of the array, leaving the original array intact
• Array.prototype.with(index, value) -> Array, returns a version of a shallow copy of the array, modified at the specific index, leaving the original array intact

as well as three new methods for TypedArray.prototype:

• TypedArray.prototype.toReversed() -> TypedArray, see above
• TypedArray.prototype.toSorted(compareFn) -> TypedArray, see above
• TypedArray.prototype.with(index, value) -> TypedArray, see above

According to their README.md, it has the following implementations

• Firefox/SpiderMonkey, currently flagged

• Safari/JavaScriptCore, shipping unflagged since Safari Tech Preview 146

• Chrome/V8, shipping unflagged since Chrome 110

• Ladybird/LibJS, shipping unflagged

• core-js

  • change-array-by-copy

• es-shims:

  • array.prototype.tosorted
  • array.prototype.toreversed
  • array.prototype.tospliced
  • array.prototype.with

• ./polyfill.js (minimalist reference implementation)