all: use bytes.Equal, bytes.Contains and strings.Contains, again

The previous cleanup was done with a buggy tool, missing some potential
rewrites.

Change-Id: I333467036e355f999a6a493e8de87e084f374e26
Reviewed-on: https://go-review.googlesource.com/21378Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/go/go_test.go

@@ -1466,7 +1466,7 @@ func TestGoTestWithPackageListedMultipleTimes(t *testing.T) {
 	defer tg.cleanup()
 	tg.parallel()
 	tg.run("test", "errors", "errors", "errors", "errors", "errors")
-	if strings.Index(strings.TrimSpace(tg.getStdout()), "\n") != -1 {
+	if strings.Contains(strings.TrimSpace(tg.getStdout()), "\n") {
 		t.Error("go test errors errors errors errors errors tested the same package multiple times")
 	}
 }
@@ -1495,7 +1495,7 @@ func TestGoListCmdOnlyShowsCommands(t *testing.T) {
 	tg.run("list", "cmd")
 	out := strings.TrimSpace(tg.getStdout())
 	for _, line := range strings.Split(out, "\n") {
-		if strings.Index(line, "cmd/") == -1 {
+		if !strings.Contains(line, "cmd/") {
 			t.Error("go list cmd shows non-commands")
 			break
 		}

src/html/template/url.go

@@ -17,7 +17,7 @@ func urlFilter(args ...interface{}) string {
 	if t == contentTypeURL {
 		return s
 	}
-	if i := strings.IndexRune(s, ':'); i >= 0 && strings.IndexRune(s[:i], '/') < 0 {
+	if i := strings.IndexRune(s, ':'); i >= 0 && !strings.ContainsRune(s[:i], '/') {
 		protocol := strings.ToLower(s[:i])
 		if protocol != "http" && protocol != "https" && protocol != "mailto" {
 			return "#" + filterFailsafe

src/net/http/serve_test.go

@@ -4267,7 +4267,7 @@ func BenchmarkClient(b *testing.B) {
 		if err != nil {
 			b.Fatalf("ReadAll: %v", err)
 		}
-		if bytes.Compare(body, data) != 0 {
+		if !bytes.Equal(body, data) {
 			b.Fatalf("Got body: %q", body)
 		}
 	}

src/path/filepath/path_test.go

@@ -1015,7 +1015,7 @@ func TestAbs(t *testing.T) {
 		vol := filepath.VolumeName(root)
 		var extra []string
 		for _, path := range absTests {
-			if strings.Index(path, "$") != -1 {
+			if strings.Contains(path, "$") {
 				continue
 			}
 			path = vol + path

src/runtime/gcinfo_test.go

@@ -59,7 +59,7 @@ func TestGCInfo(t *testing.T) {
 
 func verifyGCInfo(t *testing.T, name string, p interface{}, mask0 []byte) {
 	mask := runtime.GCMask(p)
-	if bytes.Compare(mask, mask0) != 0 {
+	if !bytes.Equal(mask, mask0) {
 		t.Errorf("bad GC program for %v:\nwant %+v\ngot  %+v", name, mask0, mask)
 		return
 	}