test: error-related fixes

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5328051

test/fixedbugs/bug365.go

@@ -12,7 +12,7 @@
 package main
 
 type S struct {
-	err os.Error  // ERROR "undefined|expected package"
+	err foo.Bar // ERROR "undefined|expected package"
 	Num int
 }
 

test/import.go

@@ -13,13 +13,12 @@ import _os_ "os"
 import "os"
 import . "os"
 
-func f(e os.Error)
+func f(e *os.File)
 
 func main() {
-	var _e_ _os_.Error
-	var dot Error
+	var _e_ *_os_.File
+	var dot *File
 
 	f(_e_)
 	f(dot)
 }
-

test/zerodivide.go

@@ -9,13 +9,10 @@ package main
 import (
 	"fmt"
 	"math"
+	"runtime"
 	"strings"
 )
 
-type Error interface {
-	String() string
-}
-
 type ErrorTest struct {
 	name string
 	fn   func()
@@ -164,7 +161,7 @@ var errorTests = []ErrorTest{
 func error(fn func()) (error string) {
 	defer func() {
 		if e := recover(); e != nil {
-			error = e.(Error).String()
+			error = e.(runtime.Error).String()
 		}
 	}()
 	fn()