RFR: (valhalla/nestmates) 8241252: Cleanup nest related logging

[David Holmes]

webrev: http://cr.openjdk.java.net/~dholmes/8241252/webrev/
bug: https://bugs.openjdk.java.net/browse/JDK-8241252

Simplification of logging logic as suggested/requested by Coleen.

Thanks,
David