[8u] RFR: 8033980: Xerces Update: datatype XMLGregorianCalendarImpl and DurationImpl

[Elliott Baron]

Hi,

I'm requesting a backport of 8033980 to 8u, as part of an update of 
Xerces to 2.12.0. Xerces should be updated for parity with Oracle JDK.

The JDK 9 fix applies cleanly except for one hunk, which was already 
patched by "8028363: XmlGregorianCalendarImpl.getTimeZone() bug when 
offset is less than 10 minutes".

Bug: https://bugs.openjdk.java.net/browse/JDK-8033980
8u Webrev: https://cr.openjdk.java.net/~ebaron/jdk8u/JDK-8033980/webrev.00/

Testing: x86_64 build, jdk_tier1, jdk_other (includes javax/xml) tests

Thanks,
Elliott