Rollup merge of #47443 - FenrirWolf:rand, r=alexcrichton
Rollup merge of #47443 - FenrirWolf:rand, r=alexcrichton

Remove leftover Rand stuff

The in-tree version of `rand` was removed in 6bc8f164b09b9994e6a2d4c4ca60d7d36c09d3fe, but for some reason this lone file avoided the purge. Figured it's about time to finish the job. :smiling_imp:

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