go/printer: remove package comment from testdata/parser.go
go/printer: remove package comment from testdata/parser.go

This prevents an incorrect summary line from appearing in the godoc
package list.

R=golang-dev, gri
CC=golang-dev
http://codereview.appspot.com/5607059
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go