Rollup merge of #85114 - jyn514:download-fixme, r=Mark-Simulacrum
Rollup merge of #85114 - jyn514:download-fixme, r=Mark-Simulacrum

Remove outdated FIXME for download-rustc

https://github.com/rust-lang/rust/pull/82739 has been merged.

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