fix bug in thread pool test
fix bug in thread pool test

AllisonWang/peloton,eric-haibin-lin/peloton-1,PauloAmora/peloton,yingjunwu/peloton,vittvolt/15721-peloton,vittvolt/15721-peloton,prashasthip/peloton,yingjunwu/peloton,eric-haibin-lin/peloton-1,haojin2/peloton,PauloAmora/peloton,apavlo/peloton,prashasthip/peloton,vittvolt/15721-peloton,apavlo/peloton,vittvolt/15721-peloton,AllisonWang/peloton,ShuxinLin/peloton,haojin2/peloton,phisiart/peloton-p3,seojungmin/peloton,PauloAmora/peloton,cmu-db/peloton,seojungmin/peloton,wangziqi2016/peloton,cmu-db/peloton,phisiart/peloton-p3,vittvolt/peloton,phisiart/peloton-p3,jessesleeping/iso_peloton,AllisonWang/peloton,jessesleeping/iso_peloton,ShuxinLin/peloton,prashasthip/peloton,AllisonWang/peloton,eric-haibin-lin/peloton-1,yingjunwu/peloton,prashasthip/peloton,wangziqi2016/peloton,haojin2/peloton,jessesleeping/iso_peloton,malin1993ml/peloton,seojungmin/peloton,prashasthip/peloton,malin1993ml/peloton,malin1993ml/peloton,cmu-db/peloton,haojin2/peloton,wangziqi2016/peloton,AngLi-Leon/peloton,vittvolt/peloton,cmu-db/peloton,ShuxinLin/peloton,yingjunwu/peloton,ShuxinLin/peloton,phisiart/peloton-p3,wangziqi2016/peloton,AllisonWang/peloton,seojungmin/peloton,vittvolt/15721-peloton,jessesleeping/iso_peloton,eric-haibin-lin/peloton-1,jessesleeping/iso_peloton,malin1993ml/peloton,wangziqi2016/peloton,prashasthip/peloton,jessesleeping/iso_peloton,AngLi-Leon/peloton,AngLi-Leon/peloton,AngLi-Leon/peloton,haojin2/peloton,vittvolt/peloton,PauloAmora/peloton,apavlo/peloton,phisiart/peloton-p3,AngLi-Leon/peloton,apavlo/peloton,apavlo/peloton,vittvolt/peloton,AngLi-Leon/peloton,cmu-db/peloton,phisiart/peloton-p3,PauloAmora/peloton,PauloAmora/peloton,cmu-db/peloton,ShuxinLin/peloton,apavlo/peloton,eric-haibin-lin/peloton-1,malin1993ml/peloton,jessesleeping/iso_peloton,ShuxinLin/peloton,malin1993ml/peloton,wangziqi2016/peloton,seojungmin/peloton,vittvolt/15721-peloton,yingjunwu/peloton,vittvolt/peloton,vittvolt/peloton,seojungmin/peloton,AllisonWang/peloton,eric-haibin-lin/peloton-1,yingjunwu/peloton,haojin2/peloton