The "KK" skeleton should return the same output as the "hh" skeleton.
This should be covered in <https://unicode.org/reports/tr35/tr35-dates.html#intervalFormats> by:
2. If no match was found from the previous step, check what the closest match is in the fallback locale chain, as in availableFormats. That is, this allows for adjusting the string value field's width, including adjusting between "MMM" and "MMMM", and using different variants of the same field, such as 'v' and 'z'.