So if you create a world with any seed, go to the end, and then create another world with the seed of the first world, except with the number 4294967296 added to it, then the end will look absolutely the same. 

Steps to reproduce: 

1. Create a world with any seed.
2. Go to the end. 
3. Create another world, with the seed of the original world + the number 4294967296 added to it. 
4. Go to the end in the new world. 
5. Compare them. 

Observed results: 

The end dimensions of both worlds look absolutely the same. 

Expected results: 

The entire end generation should depend on all 64 bits of the world seed.