Polyfill: Fix util.inspect output of polyfilled Intl.DateTimeFormat

The default formatter would look for a property called _repr_, which does
not exist, and therefore would be confusingly formatted as "undefined".
Instead, delegate to the original Intl.DateTimeFormat's util.inspect
output.

Author: ptomato

polyfill/lib/intl.mjs

@@ -30,6 +30,7 @@ import {
   EPOCHNANOSECONDS,
   ISO_DATE,
   ISO_DATE_TIME,
+  ORIGINAL,
   SetSlot,
   TIME,
   CALENDAR
@@ -41,7 +42,6 @@ const MD = SymbolCtor('md');
 const TIME_FMT = SymbolCtor('time');
 const DATETIME = SymbolCtor('datetime');
 const INST = SymbolCtor('instant');
-const ORIGINAL = SymbolCtor('original');
 const TZ_CANONICAL = SymbolCtor('timezone-canonical');
 const TZ_ORIGINAL = SymbolCtor('timezone-original');
 const CAL_ID = SymbolCtor('calendar-id');

polyfill/lib/intrinsicclass.mjs

@@ -9,6 +9,7 @@ import {
   SymbolFor,
   SymbolToStringTag
 } from './primordials.mjs';
+import { GetSlot, ORIGINAL } from './slots.mjs';
 
 import Call from 'es-abstract/2024/Call.js';
 
@@ -17,6 +18,9 @@ import ESGetIntrinsic from 'es-abstract/GetIntrinsic.js';
 const INTRINSICS = {};
 
 const customUtilInspectFormatters = {
+  ['Intl.DateTimeFormat'](depth, options, inspect) {
+    return inspect(GetSlot(this, ORIGINAL), { depth, ...options });
+  },
   ['Temporal.Duration'](depth, options) {
     const descr = options.stylize(this._repr_, 'special');
     if (depth < 1) return descr;

polyfill/lib/slots.mjs

@@ -38,6 +38,9 @@ export const MILLISECONDS = 'slot-milliseconds';
 export const MICROSECONDS = 'slot-microseconds';
 export const NANOSECONDS = 'slot-nanoseconds';
 
+// Intl.DateTimeFormat
+export const ORIGINAL = 'slot-original';
+
 const slots = new WeakMapCtor();
 export function CreateSlots(container) {
   Call(WeakMapPrototypeSet, slots, [container, ObjectCreate(null)]);