Add MILLISECOND support to DateIntervalFormat

Description

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
kIPI_MILLISECOND,

Assignee

Frank Yung-Fong Tang

Reporter

Frank Yung-Fong Tang

Components

Reviewer

None

Priority

major

Time Needed

Hours

Fix versions

Configure