message: Change Dataset.InterleaveDataset to use _should_unpack_args
  Previously it used nest.is_sequence, which was inconsistent with the
  other Dataset classes.
diff: @@ -2151,7 +2151,7 @@ class InterleaveDataset(Dataset):
  nested_args = nest.pack_sequence_as(input_dataset.output_types, args)
  - if nest.is_sequence(nested_args):
  + if _should_unpack_args(nested_args):
  dataset = map_func(*nested_args)
  else:
  dataset = map_func(nested_args)
  