Async initialization for DateFormat

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

Index: pkg/intl/data/dates/symbols/lv.json
===================================================================
--- pkg/intl/data/dates/symbols/lv.json	(revision 0)
+++ pkg/intl/data/dates/symbols/lv.json	(revision 0)
@@ -0,0 +1 @@
+{"DATEFORMATS":["EEEE, y. 'gada' d. MMMM","y. 'gada' d. MMMM","y. 'gada' d. MMM","dd.MM.yy"],"NARROWWEEKDAYS":["S","P","O","T","C","P","S"],"STANDALONESHORTMONTHS":["janv.","febr.","marts","apr.","maijs","jūn.","jūl.","aug.","sept.","okt.","nov.","dec."],"ERANAMES":["pirms mūsu ēras","mūsu ērā"],"FIRSTWEEKCUTOFFDAY":6,"NARROWMONTHS":["J","F","M","A","M","J","J","A","S","O","N","D"],"STANDALONESHORTWEEKDAYS":["Sv","Pr","Ot","Tr","Ce","Pk","Se"],"FIRSTDAYOFWEEK":0,"STANDALONEWEEKDAYS":["svētdiena","pirmdiena","otrdiena","trešdiena","ceturtdiena","piektdiena","sestdiena"],"WEEKDAYS":["svētdiena","pirmdiena","otrdiena","trešdiena","ceturtdiena","piektdiena","sestdiena"],"QUARTERS":["1. ceturksnis","2. ceturksnis","3. ceturksnis","4. ceturksnis"],"ERAS":["p.m.ē.","m.ē."],"MONTHS":["janvāris","februāris","marts","aprīlis","maijs","jūnijs","jūlijs","augusts","septembris","oktobris","novembris","decembris"],"TIMEFORMATS":["HH:mm:ss zzzz","HH:mm:ss z","HH:mm:ss","HH:mm"],"SHORTWEEKDAYS":["Sv","Pr","Ot","Tr","Ce","Pk","Se"],"SHORTQUARTERS":["C1","C2","C3","C4"],"WEEKENDRANGE":[5,6],"STANDALONENARROWWEEKDAYS":["S","P","O","T","C","P","S"],"AVAILABLEFORMATS":null,"NAME":"lv","AMPMS":["priekšpusdienā","pēcpusdienā"],"STANDALONEMONTHS":["janvāris","februāris","marts","aprīlis","maijs","jūnijs","jūlijs","augusts","septembris","oktobris","novembris","decembris"],"SHORTMONTHS":["janv.","febr.","marts","apr.","maijs","jūn.","jūl.","aug.","sept.","okt.","nov.","dec."],"STANDALONENARROWMONTHS":["J","F","M","A","M","J","J","A","S","O","N","D"]}