Review request (m): 7160728: Introduce an extra logging level for G1 logging

[Bengt Rutisson]

Hi all,

I'd like some review for this change:
http://cr.openjdk.java.net/~brutisso/7160728/webrev.00/

It introduces an extra logging level for G1. This is needed to do 
efficient performance analysis on G1 log files. Most of this will later 
on be replaced by a more general framework for the whole JVM.

This is part of the work for this CR:
7132559: G1: enhance / cleanup the PrintGCDetails output

Thanks,
Bengt