Request for approval for CR 7024697 : SessionRef.dispose() should determine if the token referred to by the token object is still valid.

[Seán Coffey]

Bug report : http://bugs.sun.com/view_bug.do?bug_id=7024697

This fix is identical to jdk 8 changeset :

http://hg.openjdk.java.net/jdk8/tl/jdk/rev/3a13b7ab57f7

regards,
Sean.