RFR (S) 8081323: ConstantPool::_resolved_references is missing in heap dump

[coleen.phillimore at oracle.com]

Summary: Add resolved_references and init_lock as hidden static field in 
class so root is found.

Tested manually with YourKit.  See bug for images.   Also ran 
serviceability tests.

open webrev at http://cr.openjdk.java.net/~coleenp/8081323.01/webrev
bug link https://bugs.openjdk.java.net/browse/JDK-8081323

Thanks,
Coleen