An instance of this class is used to generate a stream of
pseudorandom numbers. The class uses a 64-bit seed, which is
modified using a linear congruential formula.
Random64 is a pseudorandom algorithm(LCG). Therefore, we will get same sequence
if seeds are the same. This main will test how many calls nextLong() it will
get the same seed.
We do not need to save all numbers (that is too large). We could save
once every 100000 calls nextLong(). If it get a same seed, we can
detect this by calling nextLong() 100000 times continuously.