Remove similar test that does not run the result

src/test/run-pass/borrowck/borrowck-nll-iterating-and-updating.rs

-// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// compile-flags: -Z borrowck=mir -Z nll
-
-// This example comes from the NLL RFC.
-
-struct List<T> {
-    value: T,
-    next: Option<Box<List<T>>>,
-}
-
-fn to_refs<T>(list: &mut List<T>) -> Vec<&mut T> {
-    let mut list = list;
-    let mut result = vec![];
-    loop {
-        result.push(&mut list.value);
-        if let Some(n) = list.next.as_mut() {
-            list = n;
-        } else {
-            return result;
-        }
-    }
-}
-
-fn main() {
-}

src/test/run-pass/nll/mutating_references.rs

-// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
 // file at the top-level directory of this distribution and at
 // http://rust-lang.org/COPYRIGHT.
 //