Patch to

1. Shade jackson 2.x in spark-yarn-shuffle JAR: core, databind, annotation
2. Use maven antrun to verify the JAR has the renamed classes

Being Maven-based, I don't know if the verification phase kicks in on an SBT/jenkins build. It will on a `mvn install`

Author: Steve Loughran <stevel@hortonworks.com>

Closes #10780 from steveloughran/stevel/patches/SPARK-12807-master-shuffle.