add test for GetMulti with dup keys
add test for GetMulti with dup keys

danielrh/godropbox,sixolet/godropbox,dropbox/godropbox,horryq/godropbox,sixolet/godropbox,wangtuanjie/godropbox,danielrh/godropbox,icattlecoder/godropbox,dropbox/godropbox,pattyshack/godropbox,wfxiang08/godropbox,abduld/godropbox,pattyshack/godropbox,dropbox/godropbox,icattlecoder/godropbox,icattlecoder/godropbox,cch123/godropbox,abduld/godropbox,horryq/godropbox,horryq/godropbox,abduld/godropbox,wfxiang08/godropbox,cch123/godropbox,wfxiang08/godropbox,pattyshack/godropbox,gc-locks/gosqlbuilder,zj8487/godropbox,zj8487/godropbox,wangtuanjie/godropbox,zj8487/godropbox,danielrh/godropbox,sixolet/godropbox,cch123/godropbox,wangtuanjie/godropbox