Update Java VisualVM in 6ux

We like to do limited update of Java VisualVM in JDK 6u25 to address a few critical issues:
1) VisualVM project java.net is in the migration process to Kenai and Java VisualVM needs new URL to the plugin center. The old one still works, but it is not clear how long. So we should start using new one ASAP.
2) With release of JDK 7, Java VisualVM needs to address two things to work properly with JDK 7
    a) adapt to the fact that the JDK vendor is now Oracle instead of Sun
    b) fix the issue <http://netbeans.org/bugzilla/show_bug.cgi?id=191297> with the more strict classfile verification in JDK 7 (LocalVariableTypeTable, LocalVariableTable, StackMapTable attributes)
3) optionally integrate fix for CR 6988102 (rebranding issues)