Rollup merge of #107834 - zephaniahong:issue-107547-fix, r=albertlarsan68

create symlink for legacy rustfmt path

Fixes #107547 .
Main change is in the `download.rs` file. Created a symlink for the legacy rustfmt path to the new rustfmt path. Other file changes are simply as a result of porting over the symlink_file function from the Build struct to the config Struct