hg: jdk/sandbox: 8241666: Enhance log messages in ReferenceProcessor

[chris.hegarty at oracle.com]

Changeset: b95931c029be
Author:    sjohanss
Date:      2020-03-31 11:45 +0200
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/b95931c029be

8241666: Enhance log messages in ReferenceProcessor
Reviewed-by: tschatzl, sangheki

! src/hotspot/share/gc/shared/referenceProcessor.cpp
! test/hotspot/jtreg/gc/logging/TestPrintReferences.java