Revise all the calls to System.arraycopy()

[vkostyukov]

We have to make sure that we don't call it with zero elements to copy. Something like this check should be done:

if (cardinality - k > 0) {
  System.arraycopy(values, k, values, k + 1, cardinality - k);
  System.arraycopy(indices, k, indices, k + 1, cardinality - k);
}