add await class test case
add await class test case

akira-cn/thinkjs,maxzhang/thinkjs,akira-cn/thinkjs,75team/thinkjs,snadn/thinkjs,akira-cn/thinkjs,Qihoo360/thinkjs,maxzhang/thinkjs,maxzhang/thinkjs,thinkjs/thinkjs,75team/thinkjs,75team/thinkjs