NMS-6823 - fix the TopReportPluginTest

Also refactored the report plugin tests a bit to not pull in ALL
of the freakin' DAO test infrastructure just to test a simple
plugin.
Merge remote-tracking branch 'origin/1.12'

Conflicts:
	features/system-report/pom.xml
	features/system-report/src/main/java/org/opennms/systemreport/AbstractSystemReportPlugin.java
	features/system-report/src/main/java/org/opennms/systemreport/system/ThreadReportPlugin.java
	features/system-report/src/main/java/org/opennms/systemreport/system/TopReportPlugin.java
	features/system-report/src/test/java/org/opennms/systemreport/system/SystemReportPluginTest.java
	features/system-report/src/test/java/org/opennms/systemreport/system/TopReportPluginTest.java