message: Allow bijectors to handle scalar ILDJ implementations. This also fixes the BatchNorm bijector to work with event_ndims > 1.
diff: @@ -1011,12 +1011,6 @@ class Bijector(object):
  def _reduce_jacobian_det_over_event(
  self, y, ildj, min_event_ndims, event_ndims):
  """Reduce jacobian over event_ndims - min_event_ndims."""
  -
  - if not self.is_constant_jacobian:
  - return math_ops.reduce_sum(
  - ildj,
  - self._get_event_reduce_dims(min_event_ndims, event_ndims))
  -
  # In this case, we need to tile the Jacobian over the event and reduce.
  y_rank = array_ops.rank(y)
  y_shape = array_ops.shape(y)[
  