Format late arrivals with rustfmt

tests/fail/abort-terminator.rs

@@ -1,6 +1,7 @@
 #![feature(c_unwind)]
 
-extern "C" fn panic_abort() { //~ ERROR: the program aborted
+extern "C" fn panic_abort() {
+    //~ ERROR: the program aborted
     panic!()
 }
 

tests/fail/concurrency/unwind_top_of_stack.rs

@@ -10,7 +10,7 @@ extern crate libc;
 use std::{mem, ptr};
 
 extern "C-unwind" fn thread_start(_null: *mut libc::c_void) -> *mut libc::c_void {
-//~^ ERROR unwinding past the topmost frame of the stack
+    //~^ ERROR unwinding past the topmost frame of the stack
     panic!()
 }
 

tests/pass/concurrency/sync_nopreempt.rs

@@ -2,7 +2,7 @@
 // We are making scheduler assumptions here.
 // compile-flags: -Zmiri-strict-provenance -Zmiri-preemption-rate=0
 
-use std::sync::{Condvar, Mutex, Arc};
+use std::sync::{Arc, Condvar, Mutex};
 use std::thread;
 
 fn check_conditional_variables_notify_all() {