RFR 9: 8169416: SSLSessionImpl finalize overhead

[Roger Riggs]

Please review this change to remove an ineffective finalizer for 
SSLSessions.
The finalizer removes bindings from the SSLSession of a table that is also
freed when the SSLSession is being freed. There is no point in removing 
them explicitly.
It only delays freeing memory and increases the overhead due to the 
tracking
of finalizable objects.  Details are in the issue.

Webrev:
   http://cr.openjdk.java.net/~rriggs/webrev-ssl-finalize-8169416

Issue:
   https://bugs.openjdk.java.net/browse/JDK-8169416

Thanks, Roger