Add MILLISECOND support to DateIntervalFormat
This is needed to support ECMA402 PR https://github.com/tc39/ecma402/pull/347
to support the formatRange, we need to make DateIntervalFormat to support MILLISECOND
so it could handle skeleton "mmssS" "mmssSS" or "mmssSSS"
This also require to change IntervalPatternIndex in the file source/i18n/unicode/dtitvinf.h to include