Instead of passing safe prime bit length which is a kind of an
implementation detail, we should pass a public key bit length. Public
key is a Paillier modulus defining plaintext space. This information is
more important than the safe prime value/bit length used under the hood.
First of all, we should check both `p,p1` and `q,q1` in the `TestInitPsAndQs`. Moreover, it's better to operate on primes in `TestArePsAndQsGood` and in `TestInitShortcuts` because non-prime numbers are not allowed there in a real world and tests were a bit misleading because of it.
Piotr Dyraga