RFR: 8078139 : jdk.xml.dom should be loaded by the ext class loader

[huizhe wang]

Hi,

By JDK-8042244, we moved several org.w3c.dom packages to a module called 
jdk.xml.dom. This new module shall be loaded by the ext class loader.  
Please review the patch for the change.

http://cr.openjdk.java.net/~joehw/jdk9/8078139/webrev/

Thanks,
Joe