hg: shenandoah/jdk9/hotspot: Ensure BitMaps clearing is done with memset.

[ashipile at redhat.com]

Changeset: a7bdd79f5a47
Author:    shade
Date:      2017-01-31 20:07 +0100
URL:       http://hg.openjdk.java.net/shenandoah/jdk9/hotspot/rev/a7bdd79f5a47

Ensure BitMaps clearing is done with memset.

! src/share/vm/gc/shared/cmBitMap.cpp
! src/share/vm/gc/shared/cmBitMap.hpp
! src/share/vm/gc/shenandoah/shenandoahHeap.cpp