code review 5656082: test: use testlib (first 100)

test/env.go

-// $G $F.go && $L $F.$A && ./$A.out
+// run
 
 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package main
 
 import (
         "os"
         "runtime"
 )
 
 func main() {
         ga, e0 := os.Getenverror("GOARCH")
         if e0 != nil {
                 print("$GOARCH: ", e0.Error(), "\n")
                 os.Exit(1)
         }
         if ga != runtime.GOARCH {
                 print("$GOARCH=", ga, "!= runtime.GOARCH=", runtime.GOARCH, "\n")
                 os.Exit(1)
         }
         xxx, e1 := os.Getenverror("DOES_NOT_EXIST")
         if e1 != os.ENOENV {
                 print("$DOES_NOT_EXIST=", xxx, "; err = ", e1.Error(), "\n")
                 os.Exit(1)
         }
 }