Add test coverage for HTTP/2 CONNECT
Add test coverage for HTTP/2 CONNECT

cwyang/h2o,h2o/h2o,devnexen/h2o,cwyang/h2o,yannick/h2o,h2o/h2o,devnexen/h2o,h2o/h2o,cwyang/h2o,yannick/h2o,h2o/h2o,devnexen/h2o,devnexen/h2o,h2o/h2o,cwyang/h2o,cwyang/h2o,devnexen/h2o,yannick/h2o,devnexen/h2o,devnexen/h2o,h2o/h2o,yannick/h2o,cwyang/h2o,devnexen/h2o,yannick/h2o,h2o/h2o,cwyang/h2o,devnexen/h2o,cwyang/h2o,yannick/h2o,yannick/h2o,h2o/h2o,yannick/h2o,h2o/h2o,yannick/h2o