Fix test262 failures and x64 compile failure.

src/lithium-codegen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 109 matching lines @@
   char buffer[4 * KB];
   StringBuilder builder(buffer, ARRAY_SIZE(buffer));
   va_list arguments;
   va_start(arguments, format);
   builder.AddFormattedList(format, arguments);
   va_end(arguments);
 
   // Copy the string before recording it in the assembler to avoid
   // issues when the stack allocated buffer goes out of scope.
   size_t length = builder.position();
-  Vector<char> copy = Vector<char>::New(length + 1);
+  Vector<char> copy = Vector<char>::New(static_cast<int>(length) + 1);
   OS::MemCopy(copy.start(), builder.Finalize(), copy.length());
   masm()->RecordComment(copy.start());
 }
 
 
 int LCodeGenBase::GetNextEmittedBlock() const {
   for (int i = current_block_ + 1; i < graph()->blocks()->length(); ++i) {
     if (!chunk_->GetLabel(i)->HasReplacement()) return i;
   }
   return -1;
 }
 
 
 } }  // namespace v8::internal