hg: shenandoah/jdk: Shenandoah critical native support

[zgu at redhat.com]

Changeset: 232d819bc452
Author:    zgu
Date:      2018-03-28 16:27 -0400
URL:       http://hg.openjdk.java.net/shenandoah/jdk/rev/232d819bc452

Shenandoah critical native support

! src/hotspot/cpu/x86/sharedRuntime_x86_64.cpp
! src/hotspot/share/gc/shared/collectedHeap.hpp
! src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
! src/hotspot/share/gc/shenandoah/shenandoahHeap.hpp
! src/hotspot/share/runtime/sharedRuntime.cpp
! src/hotspot/share/runtime/sharedRuntime.hpp
+ test/hotspot/jtreg/gc/shenandoah/CriticalNativeStress.java
+ test/hotspot/jtreg/gc/shenandoah/libCriticalNative.c