DERBY-5667;  testReadCommitted(org.apache.derbyTesting.functionTests.tests.store.UpdateLocksTest)junit.framework.AssertionFailedError: Missing rows in ResultSet
   backport of revision 1567787 from trunk - improve error message


git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/branches/10.10@1567823 13f79535-47bb-0310-9956-ffa450edef68