hg: shenandoah/jdk: Replace ShBarrierSet* casts with accessor

[roman at kennke.org]

Changeset: c67c23538419
Author:    rkennke
Date:      2018-06-11 13:57 +0200
URL:       http://hg.openjdk.java.net/shenandoah/jdk/rev/c67c23538419

Replace ShBarrierSet* casts with accessor

! src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp
! src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.hpp
! src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.inline.hpp
! src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp
! src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
! src/hotspot/share/gc/shenandoah/shenandoahStrDedupTable.cpp
! src/hotspot/share/runtime/sharedRuntime.cpp