go/test/bench/go1: add printf and time format tests
Also rename the go parser test to GoParse so it doesn't grab the globally useful Parse name.

R=golang-dev, dave
CC=golang-dev
https://codereview.appspot.com/7732044
net/http: add tests for ParseHTTPVersion

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/7739043