DERBY-6356; java.security.AccessControlException in i18n.LocalizedDisplayScriptTest
   adding a 'setDefault' method to the test to do the calls requiring user.timezone "write" permission


git-svn-id: https://svn.apache.org/repos/asf/db/derby/code/branches/10.5@1541159 13f79535-47bb-0310-9956-ffa450edef68