Problems with tests on Diziet's machine

This routine task is currently blocked. Filing this ticket to record the known blockers:

1. https://github.com/rust-lang/cargo/issues/13667: polluted stderr output mentioning .cargo/config.toml prevents me from generating clean test cases for CI
2. https://github.com/rust-lang/rustup/issues/3737 my rustup is totally broken
3. dbg_all_keywords produces worse output because TokenStream as Display now renders ${...} as $ {...} !292 (merged)