Bug 265233

Created attachment 468721 [details]
API call in console

### Steps to reproduce the problem:

1.
const regionNames = new Intl.DisplayNames(["en"], {
  locale: "en",
  type: "region",
});

console.log(regionNames.of("HK"));
// logs "Hong Kong" instead of "Hong Kong SAR China"

2.
const longRegionNames = new Intl.DisplayNames(["en"], {
  locale: "en",
  type: "region",
  style: "long",
});
console.log(longRegionNames.of("HK"));
// logs "Hong Kong" instead of "Hong Kong SAR China"

### Problem Description:

According to the specification https://tc39.es/ecma402/#sec-intl-displaynames-constructor, Intl.displayNames().of() API should return "long" form of the region names by default.

In the current version of Safari, this API always returns the "short" version, even when "long" value is passed to "style" option.

Expected long form according to ICU module data - https://github.com/unicode-org/icu/blob/release-74-1/icu4c/source/data/region/en.txt#L138

Additional Comments:
There is no such issue on Node.js or Firefox. It is also present on Chrome browser - https://bugs.chromium.org/p/chromium/issues/detail?id=1504455.