[P2] Both engines: updating an absent arguments index bypasses its inherited setter #3517

An update of a missing numeric index on an arguments object shadows its inherited accessor instead of invoking the inherited setter.

function f(a) {
    const args = arguments;
    delete args[0];
    let writes = 0;
    let last;
    Object.setPrototypeOf(args, {
        get 0() { return 10; },
        set 0(value) { writes++; last = value; }
    });
    console.log(args[0]++, writes, last, Object.hasOwn(args, "0"), a);
}
f(1);

Node v22.23.2 prints 10 1 11 false 1. Both SharpTS engines print 10 0 undefined true 1. The compiled assembly passed full --verify. Run as an unchecked classic .js script with --no-tsconfig --noLib.

Confirmed on unchanged task baseline cabb41636, CLI SHA256 5335B14C2A96172D0372D8FCDD75264741EB8A0B19C0273737C3BBF2967D3ACE. The target slot is removed before the update, so it is independent of the parameter map. Found while checking automated review feedback on #3476 and #3473 in PR #3510. Closed #2442 concerned an inherited getter-only accessor and ordinary Array/indexed writes.