RFR: JDK-8151674: STW phases at Concurrent GC should count in PerfCounter

[Yasumasa Suenaga]

Hi all,

This review request continues from:
  http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-March/016774.html
  http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-March/016896.html

I wonder that STW phases (Remark and Cleanup) at G1 are not counted in jstat FGC column. 
For example, Initial Mark and Remark at CMS are counted as FGC. 
We discussed on hotspot-gc-dev for this issue, and I proposed to add new PerfCounter
for CGC STW phases. 

I uploaded webrev. Could you review it?
    hotspot: http://cr.openjdk.java.net/~ysuenaga/JDK-8151674/webrev.00/hotspot/
        jdk: http://cr.openjdk.java.net/~ysuenaga/JDK-8151674/webrev.00/jdk/

For compatibility, this patch works the same as the current by default.
If you set -XX:+EnableConcGCPerfCounter, CGC counter will work fine.
(I want to set +EnableConcGCPerfCounter by default)


I cannot access JPRT.
So I need a sponsor.


Thanks,

Yasumasa