RFR: 8225340: ZGC: Add logging of High Usage rule

[Stefan Karlsson]

Looks good.

StefanK

On 2019-06-05 11:31, Per Liden wrote:
> The "High Usage" rule should print a log message, like the other rules do.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8225340
> Webrev: http://cr.openjdk.java.net/~pliden/8225340/webrev.0
> 
> /Per