Revert of [wasm] Initial signal handler

src/trap-handler/handler-shared.cc

-// Copyright 2017 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// PLEASE READ BEFORE CHANGING THIS FILE!
-//
-// This file contains code that is used both inside and outside the out of
-// bounds signal handler. Because this code runs in a signal handler context,
-// use extra care when modifying this file. Here are some rules to follow.
-//
-// 1. Do not introduce any new external dependencies. This file needs
-//    to be self contained so it is easy to audit everything that a
-//    signal handler might do.
-//
-// 2. Any changes must be reviewed by someone from the crash reporting
-//    or security team. See OWNERS for suggested reviewers.
-//
-// For more information, see https://goo.gl/yMeyUY.
-
-#include "src/trap-handler/trap-handler-internal.h"
-
-namespace v8 {
-namespace internal {
-namespace trap_handler {
-
-THREAD_LOCAL bool g_thread_in_wasm_code = false;
-
-size_t gNumCodeObjects = 0;
-CodeProtectionInfoListEntry* gCodeObjects = nullptr;
-
-std::atomic_flag MetadataLock::spinlock_ = ATOMIC_FLAG_INIT;
-
-MetadataLock::MetadataLock() {
-  if (g_thread_in_wasm_code) {
-    abort();
-  }
-
-  while (spinlock_.test_and_set(std::memory_order::memory_order_acquire)) {
-  }
-}
-
-MetadataLock::~MetadataLock() {
-  if (g_thread_in_wasm_code) {
-    abort();
-  }
-
-  spinlock_.clear(std::memory_order::memory_order_release);
-}
-
-}  // namespace trap_handler
-}  // namespace internal
-}  // namespace v8