Function erase_empty_host_path 

pub fn erase_empty_host_path(url: &mut Url)

Per WHATWG URL spec, a non-special URL with an empty host can have its path erased (WPT url-setters.any.js). The url crate keeps a trailing / after the authority; reparse the serialization with it stripped when the caller has explicitly set an empty pathname on such a URL.