LUCENE-5759: Add PackedInts.unsignedBitsRequired.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1602875 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5764: Add tests to DocIdSet.ramBytesUsed.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1602877 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5765: Add tests to OrdinalMap.ramBytesUsed.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1602881 13f79535-47bb-0310-9956-ffa450edef68