Add basic tests for additional MirrorServer features

git-svn-id: https://svn.apache.org/repos/asf/jmeter/trunk@1577864 13f79535-47bb-0310-9956-ffa450edef68
Close streams; trim trailing spaces

git-svn-id: https://svn.apache.org/repos/asf/jmeter/trunk@1577865 13f79535-47bb-0310-9956-ffa450edef68