RFR 9: 8038490: java.time Using IsoFields.WEEK_BASED_YEAR

[roger riggs]

Please review this correction to java.time week_based_year:
8038490 <https://bugs.openjdk.java.net/browse/JDK-8038490>: Using 
IsoFields.WEEK_BASED_YEAR with ZonedDateTime throws ClassCastException

Webrev:
 http://cr.openjdk.java.net/~rriggs/webrev-week-based-year-8038490/

Thanks, Roger