DERBY-6176 (Couple failures in SequenceGeneratorTest suite on trunk(1466748) with weme 6.2)

backporting it to 10.10



git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/branches/10.10@1467634 13f79535-47bb-0310-9956-ffa450edef68