OAK-1998: Accessible tree below a non-accessible parent are HiddenTree
Only return HiddenTree instances for actually hidden trees, not for inaccessible trees

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1614397 13f79535-47bb-0310-9956-ffa450edef68
OAK-2001 TarMk compaction can still cause repository growth



git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1614405 13f79535-47bb-0310-9956-ffa450edef68