DERBY-6017  IN lists with mixed types may return wrong results

merged from trunk 1424889, 1448025, 1450695
Contrubuted by Knut Anders Hatlen



git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/branches/10.8@1511288 13f79535-47bb-0310-9956-ffa450edef68