Date discreapncies between Formatter::asDate() and FormatConverter::convertDateIcuToJui() discrepancies

[yii-bot]

This issue has originally been reported by @tom-- at yiisoft/yii2#9312.
Moved here by @cebe.

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I noticed the following differences when using jQuery-UI Datepicker. Formatter was providing the date input's initial value on page load and the format changed after using Datepicker.

Both are ICU 'medium'.

locale	asDate()	convertDateIcuToJui()
en-US	Apr 4, 2015	Apr 4 2015
ru-RU	04 авг. 2015 г.	04 Авг 2015 г.

or something like that

[buddh4]

This language file seems to work.