message: Fix Model.evaluate sync logic
diff: @@ -1084,7 +1084,7 @@ class Model(network.Network, version_utils.ModelVersionSelector):
  with trace.Trace('TraceContext', graph_type='test', step_num=step):
  callbacks.on_test_batch_begin(step)
  tmp_logs = test_function(iterator)
  - if not data_handler.should_sync:
  + if data_handler.should_sync:
  context.async_wait()
  logs = tmp_logs # No error, now safe to assign to logs.
  callbacks.on_test_batch_end(step, logs)
  