hg: jdk9/hs-rt/hotspot: 8138920: Refactor the sampling thread from ConcurrentG1RefineThread

[per.liden at oracle.com]

Changeset: c664861faadc
Author:    drwhite
Date:      2015-10-26 12:22 -0400
URL:       http://hg.openjdk.java.net/jdk9/hs-rt/hotspot/rev/c664861faadc

8138920: Refactor the sampling thread from ConcurrentG1RefineThread
Summary: Helps enable running without concurrent refinement threads
Reviewed-by: brutisso, pliden

! src/share/vm/gc/g1/concurrentG1Refine.cpp
! src/share/vm/gc/g1/concurrentG1Refine.hpp
! src/share/vm/gc/g1/concurrentG1RefineThread.cpp
! src/share/vm/gc/g1/concurrentG1RefineThread.hpp
! src/share/vm/gc/g1/concurrentMarkThread.cpp
! src/share/vm/gc/g1/concurrentMarkThread.hpp
+ src/share/vm/gc/g1/g1YoungRemSetSamplingThread.cpp
+ src/share/vm/gc/g1/g1YoungRemSetSamplingThread.hpp
! src/share/vm/gc/shared/concurrentGCThread.cpp