THRFIT-804. java: CompareTo is broken for unions set to map, set, or list

This patch fixes TUnion's compareTo, and factors out the standard part of the comparison to TBaseHelper.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@957350 13f79535-47bb-0310-9956-ffa450edef68
4 files changed