message: Fix ci/big_rand for u64 bits
diff: @@ -102,7 +102,7 @@ mod biguint {
  let mut rng = R::from_seed(seed);
  for (i, &s) in expected.iter().enumerate() {
  let n: BigUint = s.parse().unwrap();
  - let r = rng.gen_biguint((1 << i) + i);
  + let r = rng.gen_biguint((1 << i) + i as u64);
  assert_eq!(n, r);
  }
  }
  @@ -302,7 +302,7 @@ mod bigint {
  let mut rng = R::from_seed(seed);
  for (i, &s) in expected.iter().enumerate() {
  let n: BigInt = s.parse().unwrap();
  - let r = rng.gen_bigint((1 << i) + i);
  + let r = rng.gen_bigint((1 << i) + i as u64);
  assert_eq!(n, r);
  }
  }
  