unix: use ByteSliceToString in TestIoctlPtmget

Change-Id: I42cb5be80246af76cca9b6a09c6cb85bc07ab081
Reviewed-on: https://go-review.googlesource.com/c/sys/+/407254
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
diff --git a/unix/syscall_netbsd_test.go b/unix/syscall_netbsd_test.go
index 2316d26..aac4320 100644
--- a/unix/syscall_netbsd_test.go
+++ b/unix/syscall_netbsd_test.go
@@ -5,7 +5,6 @@
 package unix_test
 
 import (
-	"bytes"
 	"os"
 	"testing"
 
@@ -39,7 +38,7 @@
 		t.Fatalf("IoctlGetPtmget: %v\n", err)
 	}
 
-	t.Logf("sfd = %v, ptsname = %v", ptm.Sfd, string(ptm.Sn[:bytes.IndexByte(ptm.Sn[:], 0)]))
+	t.Logf("sfd = %v, ptsname = %v", ptm.Sfd, unix.ByteSliceToString(ptm.Sn[:]))
 }
 
 func TestStatvfs(t *testing.T) {