tests: check for global leaks
tests: check for global leaks

expressjs/serve-index,thaiat/serve-index,jsl9208/koa2-serve-index,thaiat/serve-index,jsl9208/koa2-serve-index,adamarthurryan/serve-index,yiminghe/koa-serve-index,yiminghe/koa-serve-index,adamarthurryan/serve-index,expressjs/serve-index