Async initialization for DateFormat

pkg/intl/data/dates/symbols/uk.json

Index: pkg/intl/data/dates/symbols/uk.json
===================================================================
--- pkg/intl/data/dates/symbols/uk.json	(revision 0)
+++ pkg/intl/data/dates/symbols/uk.json	(revision 0)
@@ -0,0 +1 @@
+{"DATEFORMATS":["EEEE, d MMMM y 'р'.","d MMMM y 'р'.","d MMM y","dd.MM.yy"],"NARROWWEEKDAYS":["Н","П","В","С","Ч","П","С"],"STANDALONESHORTMONTHS":["Січ","Лют","Бер","Кві","Тра","Чер","Лип","Сер","Вер","Жов","Лис","Гру"],"ERANAMES":["до нашої ери","нашої ери"],"FIRSTWEEKCUTOFFDAY":6,"NARROWMONTHS":["С","Л","Б","К","Т","Ч","Л","С","В","Ж","Л","Г"],"STANDALONESHORTWEEKDAYS":["Нд","Пн","Вт","Ср","Чт","Пт","Сб"],"FIRSTDAYOFWEEK":0,"STANDALONEWEEKDAYS":["Неділя","Понеділок","Вівторок","Середа","Четвер","Пʼятниця","Субота"],"WEEKDAYS":["Неділя","Понеділок","Вівторок","Середа","Четвер","Пʼятниця","Субота"],"QUARTERS":["I квартал","II квартал","III квартал","IV квартал"],"ERAS":["до н.е.","н.е."],"MONTHS":["січня","лютого","березня","квітня","травня","червня","липня","серпня","вересня","жовтня","листопада","грудня"],"TIMEFORMATS":["HH:mm:ss zzzz","HH:mm:ss z","HH:mm:ss","HH:mm"],"SHORTWEEKDAYS":["Нд","Пн","Вт","Ср","Чт","Пт","Сб"],"SHORTQUARTERS":["I кв.","II кв.","III кв.","IV кв."],"WEEKENDRANGE":[5,6],"STANDALONENARROWWEEKDAYS":["Н","П","В","С","Ч","П","С"],"AVAILABLEFORMATS":null,"NAME":"uk","AMPMS":["дп","пп"],"STANDALONEMONTHS":["Січень","Лютий","Березень","Квітень","Травень","Червень","Липень","Серпень","Вересень","Жовтень","Листопад","Грудень"],"SHORTMONTHS":["січ.","лют.","бер.","квіт.","трав.","черв.","лип.","серп.","вер.","жовт.","лист.","груд."],"STANDALONENARROWMONTHS":["С","Л","Б","К","Т","Ч","Л","С","В","Ж","Л","Г"]}