Named seeds that are not numbers are not being recognized

To Reproduce

1. Create a world with seed a in 20w20a.
2. Check the seed by using /seed command.
   • Expected: 97
   • Actual: a random number

Original Description

In the latest snapshot I tried using a world generated with the seed "a", which should be seed "97".

However in this snapshot the seed I received was much longer, and resembled a seed that would generate randomly. I tried the same "a" seed again, and I received a different seed yet again. I tried this with other words and they all give back random seeds. When I tried the seed "1" the world generated with the seed "1", which leads me to believe this is only the case for seeds made up of letters.