hg: jdk/submit: JDK-8204947: Port ShenandoahTaskTerminator to mainline and make it default

[zgu at redhat.com]

Changeset: a2ff31ddca51
Author:    zgu
Date:      2018-11-28 08:20 -0500
URL:       http://hg.openjdk.java.net/jdk/submit/rev/a2ff31ddca51

JDK-8204947: Port ShenandoahTaskTerminator to mainline and make it default

! src/hotspot/share/gc/g1/g1ConcurrentMark.cpp
! src/hotspot/share/gc/g1/g1ConcurrentMark.hpp
! src/hotspot/share/gc/g1/g1FullGCReferenceProcessorExecutor.hpp
! src/hotspot/share/gc/parallel/pcTasks.cpp
! src/hotspot/share/gc/parallel/psParallelCompact.cpp
! src/hotspot/share/gc/parallel/psScavenge.cpp
! src/hotspot/share/gc/shared/gc_globals.hpp
+ src/hotspot/share/gc/shared/owstTaskTerminator.cpp
+ src/hotspot/share/gc/shared/owstTaskTerminator.hpp
! src/hotspot/share/gc/shared/taskqueue.cpp
! src/hotspot/share/gc/shared/taskqueue.hpp