Codereview request: 8023529 OpenMBeanInfoSupport.equals/hashCode throw NPE

[shanliang]

I have added 2 tasts to make sure that call 
OpenMBean*InfoSupport.equals/hashCode do not throw NPE
The unit tests and JCK tests are passed.

Webrev: http://cr.openjdk.java.net/~sjiang/JDK-8023529/00/
Bug: https://bugs.openjdk.java.net/browse/JDK-8023529
Thanks,

Shanliang