go/*: fix pre-1.11 tests

packagestest.Modules is now available pre-go1.11 but doesn't add
itself to packagestest.All.

strings.ReplaceAll is not available in pre-go1.11

Change-Id: Ia8bf0e82bb853c6f29d31ca5c54651097342b19c
Reviewed-on: https://go-review.googlesource.com/c/143419
Reviewed-by: Ian Cottrell <iancottrell@google.com>

go/analysis/multichecker/multichecker.go

@@ -53,7 +53,7 @@ func Main(analyzers ...*analysis.Analyzer) {
 
 	args := flag.Args()
 	if len(args) == 0 {
-		fmt.Fprintln(os.Stderr, strings.ReplaceAll(usage, "PROGNAME", progname))
+		fmt.Fprintln(os.Stderr, strings.Replace(usage, "PROGNAME", progname, -1))
 		fmt.Fprintf(os.Stderr, "Run '%[1]s help' for more detail,\n"+
 			" or '%[1]s help name' for details and flags of a specific analyzer.\n",
 			progname)
@@ -73,7 +73,7 @@ func Main(analyzers ...*analysis.Analyzer) {
 func help(progname string, analyzers []*analysis.Analyzer, args []string) {
 	// No args: show summary of all analyzers.
 	if len(args) == 0 {
-		fmt.Println(strings.ReplaceAll(usage, "PROGNAME", progname))
+		fmt.Println(strings.Replace(usage, "PROGNAME", progname, -1))
 		fmt.Println("Registered analyzers:")
 		fmt.Println()
 		sort.Slice(analyzers, func(i, j int) bool {

go/packages/packagestest/modules.go

@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build go1.11
-
 package packagestest
 
 import (
@@ -34,10 +32,6 @@ import (
 //     /sometemporarydirectory/repoa
 var Modules = modules{}
 
-func init() {
-	All = append(All, Modules)
-}
-
 type modules struct{}
 
 func (modules) Name() string {

go/packages/packagestest/modules_111.go

@@ -0,0 +1,7 @@
+// +build go1.11
+
+package packagestest
+
+func init() {
+	All = append(All, Modules)
+}