message: Add some trace to identify the type of device we are executing upon
  Summary: Useful trace at the moment - and maybe useful in the long run too
  Test Plan: None
  Reviewers: georgep
diff: @@ -714,6 +714,11 @@ StatusOr<se::DeviceMemoryBase> PoplarExecutor::ExecuteEngine(
  AllocateOutputBuffer(allocator, output_shape, 0, output_map, args,
  executable.OutputStreamed());
  + auto target_type_name =
  + poplar::toString(poplar_device_.getTarget().getTargetType());
  +
  + VLOG(1) << "Executing on poplar device type " << target_type_name;
  +
  try {
  const auto& streamed = executable.OutputStreamed();
  std::vector<void*> bufs;
  