CLDR data changed so that <fields> is now a sibling of <calendars> rather than a child of <calendar>, but for backwards compatibility, associating the data in <fields> with each <calendar> when we output JSON files for the calendars.   Unfortunately for some reason this changes the order of keys in some of the files.  That shouldn't matter for JSON, but it makes the diff bigger than it really is.

Checkin split into multiple parts due to size.

Fixes #17071 !strict.