hg: shenandoah/jdk11: [backport] Simplify Shenandoah task termination in aborted paths

[zgu at redhat.com]

Changeset: eefd364ff6b5
Author:    zgu
Date:      2018-12-14 08:20 -0500
URL:       http://hg.openjdk.java.net/shenandoah/jdk11/rev/eefd364ff6b5

[backport] Simplify Shenandoah task termination in aborted paths

! src/hotspot/share/gc/shenandoah/shenandoahConcurrentMark.cpp
! src/hotspot/share/gc/shenandoah/shenandoahTaskqueue.cpp
! src/hotspot/share/gc/shenandoah/shenandoahTaskqueue.hpp
! src/hotspot/share/gc/shenandoah/shenandoahTraversalGC.cpp