DERBY-5630; intermittent test failure in store/lockTableVTI.sql
  converting the lockTableVti.sql to LockTableVtiTest and take advantage of improved timing control.


git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/trunk@1564608 13f79535-47bb-0310-9956-ffa450edef68