Intl: Tibetan / Dzongkha collation not working

[eroux]

Hello,

The Intl collator object doesn't handle Tibetan / Dzongkha collation correctly. I've setup a small test on http://eroux.fr/locales.html and the output of Edge 15 on Windows 10 is

May or may not be related to http://bugs.icu-project.org/trac/ticket/13224

[eroux]

a pure javascript version of the test:

var supportedLocales = Intl.Collator.supportedLocalesOf(['dz','bo']).join(", ");
var tibCollator = new Intl.Collator('dz');
var tibSortedArray = ["ང", "རྔ", "ལྔ", "སྔ", "བརྔ", "བསྔ", "ཅ"];
var tibRandomArray = ["ལྔ", "ང", "ཅ", "རྔ", "སྔ", "བརྔ", "བསྔ"];
var tibResultArray = ["ལྔ", "ང", "ཅ", "རྔ", "སྔ", "བརྔ", "བསྔ"];
tibResultArray.sort(tibCollator.compare);
var resPrint = "";
console.log("Tibetan/Dzongkha locales advertized as supported for collation: "+supportedLocales);
if (JSON.stringify(tibSortedArray)==JSON.stringify(tibResultArray)) {
  console.log("test passed!");
} else {
  console.log("error: "+JSON.stringify(tibRandomArray)+" has been sorted as "+JSON.stringify(tibResultArray)+", should have been "+JSON.stringify(tibSortedArray));
}

[dilijev]

Tracking as part of #3644