hg: shenandoah/jdk11: JDK11: Silence compilation warnings on implicit type conversion

[zgu at redhat.com]

Changeset: 8f04a8d6efe4
Author:    zgu
Date:      2018-09-04 14:56 -0400
URL:       http://hg.openjdk.java.net/shenandoah/jdk11/rev/8f04a8d6efe4

JDK11: Silence compilation warnings on implicit type conversion

! src/hotspot/share/gc/shared/parallelCleaning.cpp