hg: shenandoah/jdk11: Fix dangling write-barrier in acmp

[roman at kennke.org]

Changeset: 2fa9c7a0183f
Author:    rkennke
Date:      2018-12-12 15:55 +0100
URL:       http://hg.openjdk.java.net/shenandoah/jdk11/rev/2fa9c7a0183f

Fix dangling write-barrier in acmp

! src/hotspot/share/opto/subnode.cpp