OAK-2207 Add a Scalabilty test for measuring...

little steps before switching
OAK-2248 - IndexOutOfBoundsException in o.a.j.o.scalability.ScalabilityNodeRelationshipSuite

Re-initiated the NODE_LEVELS value with proper defaults

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1635458 13f79535-47bb-0310-9956-ffa450edef68
Merge branch 'upstream-trunk' into OAK-2207
OAK-2207

wip on the scalabiltiy test