polyfill: format for `Date` and Temporal classes are different in `Intl.DateTimeFormat` for some locales and options

[fabon-f]

new Intl.DateTimeFormat("ja", { month: "short", day: "numeric" }).format(0);
// "1月1日"
new Intl.DateTimeFormat("ja", { month: "short", day: "numeric" }).format(Temporal.PlainDateTime.from("1970-01-01"));
// "1/1"

(note: V8 also has this problem for some reason. SpiderMonkey doesn't.)

This is because options in Intl.DateTimeFormat and resolvedOptions are not roundtrippable for some cases:

new Intl.DateTimeFormat("ja", { month: "short", day: "numeric" }).resolvedOptions().month;
// "numeric", not "short"
new Intl.DateTimeFormat("ja", { month: "numeric", day: "numeric" });
// different format is chosen when recreating `Intl.DateTimeFormat` from the return value of `resolvedOptions`

I found many combinations of locales and options which produce different result for Temporal classes and Date. I verified this on Node.js and Firefox. Some of them are practically nonsense (e.g. combination of era and month), but still there are bunch of cases.

// Turkish
new Intl.DateTimeFormat('tr', { year: 'numeric', month: 'numeric' }).resolvedOptions().month;
// "2-digit", not "numeric"
new Intl.DateTimeFormat('tr', { year: 'numeric', month: 'numeric' }).format(0);
// "01/1970"
new Intl.DateTimeFormat('tr', { year: 'numeric', month: 'numeric' }).format(Temporal.PlainDateTime.from('1970-01-01'));
// "01.1970"

Script I used to discover these exceptions: https://gist.github.com/fabon-f/d6b22aa3d3c816cabdea2510c8d9b322

[ptomato]

I believe this is the same or similar problem as #3062

I probably won't plan to fix this in the polyfill. We are going to archive this repo soon.

Is there anything here that we could add to test262 that wouldn't fall under implementation- and locale-defined behaviour?