RFR: 8221153: ZGC: Heap iteration and verification pollutes GC statistics

[Per Liden]

Thanks Stefan!

/Per

On 3/28/19 11:56 AM, Stefan Karlsson wrote:
> Looks good.
> 
> StefanK
> 
> On 2019-03-27 22:54, Per Liden wrote:
>> When performing heap iteration and verification we should disable 
>> ZStatTimers to avoid polluting the GC statistics. This can otherwise 
>> look very odd in GC logs, with statistics that is hard to interpret 
>> since the times recorded doesn't come from a GC pause.
>>
>> This patch introduces ZStatTimerDisable, which can be placed in scopes 
>> where we want ZStatTimers to be disabled.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8221153
>> Webrev: http://cr.openjdk.java.net/~pliden/8221153/webrev.0
>>
>> /Per