update etcd cluster test helper functions
update etcd cluster test helper functions

taskgraph/taskgraph,fengjingchao/taskgraph,go-distributed/meritop,plutoshe/taskgraph,5kg/taskgraph,go-distributed/meritop,5kg/taskgraph,taskgraph/taskgraph,plutoshe/mapreduceOfTaskgraph,kod3r/taskgraph,fengjingchao/taskgraph,dzch/taskgraph,dzch/taskgraph,plutoshe/mapreduceOfTaskgraph,BaiGang/taskgraph,plutoshe/taskgraph,BaiGang/taskgraph,kod3r/taskgraph