Auto merge of #890 - RalfJung:xargo, r=RalfJung

go back to released xargo (the experiment is done)

The experiment in https://github.com/rust-lang/rust/pull/63162 was successful, now we have to wait for a new xargo release.

src/bin/cargo-miri.rs

@@ -250,8 +250,7 @@ fn setup(ask_user: bool) {
             println!("Installing xargo: `cargo install xargo -f`");
         }
 
-        // FIXME: Install from crates.io again once a new xargo got released.
-        if cargo().args(&["install", "xargo", "-f", "--git", "https://github.com/japaric/xargo"]).status()
+        if cargo().args(&["install", "xargo", "-f"]).status()
             .expect("failed to install xargo")
             .success().not()
         {