This is based on UTS35 in the new spec.

Add test for case of -kn-true
Verify no -kn-true nor -kn-false in the returned locale.
Change expectation per https://github.com/tc39/ecma402/pull/302

See https://tc39.github.io/proposal-intl-locale/#sec-canonicalizelocalelist

This is due to the fact we now only accept Unicode Locale Identifier in
UTS 35.

Sync with https://github.com/tc39/proposal-intl-list-format/pull/36

https://github.com/tc39/proposal-intl-segmenter/pull/55

Increase coverage for the Intl.DateTimeFormat constructor by adding a
test that confirms that ToObject(...) is appropriately called inside the
implementation.

Increase coverage for the Intl.DateTimeFormat constructor by adding a
test that checks for the default values.

Based on: https://github.com/tc39/test262/blob/44fc8165d54de9c9f0128f70eda56bdcb5dde82c/implementation-contributed/v8/intl/segmenter/segment-iterator-ownPropertyDescriptor.js

Fix wrong expectations of
Intl.RelativeTimeFormat.prototype.formatToParts
Add tests to cover "group", "decimal" and "fraction".

Fixes #1904