message: fix buf address for tuples
diff: @@ -47,13 +47,14 @@ static se::DeviceMemoryBase AllocateOutputBuffer(sep::ExecutorExecutor* executor
  } else {
  int64 size(xla::ShapeUtil::ByteSizeOf(shape, sizeof(void*)));
  void** buf = reinterpret_cast<void**>(executor->Allocate(size));
  + void** buf_rc = buf;
  for (int64 n = 0; n < xla::ShapeUtil::TupleElementCount(shape); n++) {
  se::DeviceMemoryBase out =
  AllocateSingleOutput(executor, literal.tuple_literals(n));
  *buf++ = out.opaque();
  }
  - return se::DeviceMemoryBase(buf, size);
  + return se::DeviceMemoryBase(buf_rc, size);
  }
  }
  