fix test tree topo
fix test tree topo

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