Deprecated version of multihead_attention_params with combine=True.

def multihead_attention_vars(
    mesh, heads, io_channels, kv_channels,
    master_dtype, slice_dtype, activation_dtype):
  """Deprecated version of multihead_attention_params with combine=True."""
  return multihead_attention_params(
      mesh, heads, io_channels, kv_channels,
      mtf.VariableDType(master_dtype, slice_dtype, activation_dtype),
      combine=True)