hg: shenandoah/jdk10: Relax assert in SBS::is_safe()

[roman at kennke.org]

Changeset: 3a6457fecc72
Author:    rkennke
Date:      2018-01-24 15:09 +0100
URL:       http://hg.openjdk.java.net/shenandoah/jdk10/rev/3a6457fecc72

Relax assert in SBS::is_safe()

! src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp