WebCore::weekDayShortLabels() for ICU always returns the fallback labels

WebCore::weekDayShortLabels() for ICU always returns the fallback labels
https://bugs.webkit.org/show_bug.cgi?id=83991

Reviewed by Hajime Morita.

We need to specfiy 1-based index to udat_getSymbols() with
UDAT_SHORT_WEEKDAYS. Also, udat_countSymbols() with UDAT_SHORT_WEEKDAYS
returns 8.

No new tests because this behavior depends on locale setting.

* platform/text/LocalizedCalendarICU.cpp:
(WebCore::createLabelVector): Add startIndex argument.
(WebCore::createMonthLabels):
Pass UDAT_JANUARRY(0) as startIndex to createLabelVector().
(WebCore::createWeekDayShortLabels):
Pass UDAT_SUNDAY(1) as startIndex to createLabelVector().

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@114224 268f45cc-cd09-0410-ab3c-d52691b4dbfc