Revert "change skolemizations to use universe index"
Revert "change skolemizations to use universe index"

This reverts commit 755bdaa19084c3ae116ad8320b99a6932fa7f0b1.

graydon/rust,GBGamer/rust,aidancully/rust,aidancully/rust,GBGamer/rust,graydon/rust,GBGamer/rust,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,GBGamer/rust,graydon/rust,aidancully/rust