RFR: [9] 8042360: Subtag syntax check is incomplete in Locale.LanguageRange

[Yuka Kamiya]

Hello,

Please review a simple fix for JDK 9:

Bug description: https://bugs.openjdk.java.net/browse/JDK-8042360
Webrev: http://cr.openjdk.java.net/~peytoia/8042360/webrev.00/

Thanks,
--
Yuka