Fix cluster-fuzz regression with Workers when serializing empty string

src/d8.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.
 
 
 // Defined when linking against shared lib on Windows.
 #if defined(USING_V8_SHARED) && !defined(V8_SHARED)
 #define V8_SHARED
 #endif
 
@@ skipping 1520 matching lines @@
     ArrayBuffer::Contents& contents = array_buffer_contents[i];
     Shell::array_buffer_allocator->Free(contents.Data(), contents.ByteLength());
   }
 }
 
 
 void SerializationData::WriteTag(SerializationTag tag) { data.Add(tag); }
 
 
 void SerializationData::WriteMemory(const void* p, int length) {
-  i::Vector<uint8_t> block = data.AddBlock(0, length);
-  memcpy(&block[0], p, length);
+  if (length > 0) {
+    i::Vector<uint8_t> block = data.AddBlock(0, length);
+    memcpy(&block[0], p, length);
+  }
 }
 
 
 void SerializationData::WriteArrayBufferContents(
     const ArrayBuffer::Contents& contents) {
   array_buffer_contents.Add(contents);
   WriteTag(kSerializationTagTransferredArrayBuffer);
   int index = array_buffer_contents.length() - 1;
   Write(index);
 }
@@ skipping 844 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif