add benchmarks for iteration.go
add benchmarks for iteration.go

daemonchen/goquery,ASAPPinc/goquery,ASAPPinc/goquery,cmars/tools,yinzhiqiang/goquery,legendtkl/goquery,cmars/tools,ASAPPinc/goquery,tjyang/goquery,qida/goquery,legendtkl/goquery,daemonchen/goquery,PuerkitoBio/goquery,matrixik/goquery,cmars/tools,jjz/goquery,jjz/goquery,jjz/goquery,tjyang/goquery,qida/goquery,tjyang/goquery,qida/goquery,mantyr/goquery,treejames/goquery,yinzhiqiang/goquery,daemonchen/goquery,mantyr/goquery,zhangheli/goquery,yinzhiqiang/goquery,zhangheli/goquery,treejames/goquery,PuerkitoBio/goquery,zhangheli/goquery,treejames/goquery,cmars/tools,legendtkl/goquery