hg: shenandoah/jdk: Add flag to switch between WB and RB-based acmp

[roman at kennke.org]

Changeset: d6ea41bbfcba
Author:    rkennke
Date:      2018-08-31 22:20 +0200
URL:       http://hg.openjdk.java.net/shenandoah/jdk/rev/d6ea41bbfcba

Add flag to switch between WB and RB-based acmp

! src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp
! src/hotspot/share/gc/shenandoah/shenandoah_globals.hpp