Update to latest JaCoCo 0.6.4

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1553521 13f79535-47bb-0310-9956-ffa450edef68
Remove unnecessary separate length, an array already has one

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1553522 13f79535-47bb-0310-9956-ffa450edef68