message: Change accumulator count dtype to int64
diff: @@ -177,7 +177,7 @@ class _NormalizingCombiner(Combiner):
  reduction_counts = np.delete(values.shape, self.axis)
  # We get the number of elements that will be reduced by multiplying all
  # values of 'shape' corresponding to the reduced axes.
  - count = np.prod(reduction_counts, dtype=np.int32)
  + count = np.prod(reduction_counts, dtype=np.int64)
  # We want to reduce across dimensions except those specified in 'axis'
  # when using np.mean or np.variance; create the tuple of axes to reduce
  