Keep prototype maps in dictionary mode until ICs see them

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 3831 matching lines @@
 bool v8::Object::SetPrototype(Local<Value> value) {
   auto context = ContextFromHeapObject(Utils::OpenHandle(this));
   return SetPrototype(context, value).FromMaybe(false);
 }
 
 
 Local<Object> v8::Object::FindInstanceInPrototypeChain(
     v8::Local<FunctionTemplate> tmpl) {
   auto isolate = Utils::OpenHandle(this)->GetIsolate();
   i::PrototypeIterator iter(isolate, *Utils::OpenHandle(this),
-                            i::PrototypeIterator::START_AT_RECEIVER);
+                            i::kStartAtReceiver);
   auto tmpl_info = *Utils::OpenHandle(*tmpl);
   while (!tmpl_info->IsTemplateFor(iter.GetCurrent())) {
     iter.Advance();
     if (iter.IsAtEnd()) {
       return Local<Object>();
     }
   }
   // IsTemplateFor() ensures that iter.GetCurrent() can't be a Proxy here.
   return Utils::ToLocal(i::handle(iter.GetCurrent<i::JSObject>(), isolate));
 }
@@ skipping 4950 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