Refactor BPFTesterCompatibilityDelegate to use AuxHolder instead

sandbox/linux/seccomp-bpf/bpf_tester_compatibility_delegate.cc

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "sandbox/linux/seccomp-bpf/bpf_tester_compatibility_delegate.h"
-
-namespace sandbox {
-
-// static
-template <>
-void* BPFTesterCompatibilityDelegate<void>::NewAux() {
-  return NULL;
-}
-
-// static
-template <>
-void BPFTesterCompatibilityDelegate<void>::DeleteAux(void* aux) {
-  CHECK(!aux);
-}
-
-}  // namespace sandbox