httputil: fix tests
httputil: fix tests

reintroduce NewSingleHostReverseProxy to fix the tests
seems the TestNilBody test is no longer relevant

attilagyorffy/puma-dev,puma/puma-dev,attilagyorffy/puma-dev,attilagyorffy/puma-dev,puma/puma-dev,puma/puma-dev,puma/puma-dev,attilagyorffy/puma-dev