net/http: make a test fail harder, earlier
net/http: make a test fail harder, earlier

LGTM=dave
R==r, r, dave
CC=golang-codereviews
https://codereview.appspot.com/59810043

d0f/go-zh,rdp/rogerpack2005-golang,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,sanjosh/sanjos100-tipc,rdp/rogerpack2005-golang,d0f/go-zh,d0f/go-zh,rdp/rogerpack2005-golang,rdp/rogerpack2005-golang,glycerine/jeaten-go-arrayof-structof,webfd/go-zh,sanjosh/sanjos100-tipc,bryanxu/go-zh,rdp/rogerpack2005-golang,webfd/go-zh,sanjosh/sanjos100-tipc,webfd/go-zh,d0f/go-zh,sanjosh/sanjos100-tipc,bryanxu/go-zh,webfd/go-zh,bryanxu/go-zh,webfd/go-zh,rdp/rogerpack2005-golang,webfd/go-zh,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,sanjosh/sanjos100-tipc,bryanxu/go-zh,sanjosh/sanjos100-tipc,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,bryanxu/go-zh,webfd/go-zh,d0f/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,webfd/go-zh,sanjosh/sanjos100-tipc,bryanxu/go-zh,bryanxu/go-zh,glycerine/jeaten-go-arrayof-structof,bryanxu/go-zh