hg: shenandoah/jdk: RP closures should accept NULL referents

[ashipile at redhat.com]

Changeset: c90391618b2f
Author:    shade
Date:      2018-02-23 13:07 +0100
URL:       http://hg.openjdk.java.net/shenandoah/jdk/rev/c90391618b2f

RP closures should accept NULL referents

! src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp
+ test/hotspot/jtreg/gc/shenandoah/acceptance/RefprocSanity.java