Revert of Pool implementation for zone segments

src/api.cc

 // Copyright 2012 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.
 
 #include "src/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 8223 matching lines @@
 
 
 void Isolate::IsolateInBackgroundNotification() {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   return isolate->IsolateInBackgroundNotification();
 }
 
 void Isolate::MemoryPressureNotification(MemoryPressureLevel level) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   isolate->heap()->MemoryPressureNotification(level, Locker::IsLocked(this));
-  isolate->allocator()->MemoryPressureNotification(level);
 }
 
 void Isolate::SetRAILMode(RAILMode rail_mode) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
   return isolate->SetRAILMode(rail_mode);
 }
 
 void Isolate::SetJitCodeEventHandler(JitCodeEventOptions options,
                                      JitCodeEventHandler event_handler) {
   i::Isolate* isolate = reinterpret_cast<i::Isolate*>(this);
@@ skipping 1117 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8