Ignore a test (#2053)

* Disable chksum: test_arg_overrides_stdin
fails often with:

---- test_cksum::test_arg_overrides_stdin stdout ----
current_directory_resolved:
touch: /tmp/.tmpv9hydc/a
run: /target/x86_64-unknown-linux-gnu/debug/coreutils cksum a
thread 'test_cksum::test_arg_overrides_stdin' panicked at 'Broken pipe (os error 32)', tests/common/util.rs:742:37
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

* rustfmt the recent change

tests/by-util/test_cksum.rs

@@ -35,6 +35,7 @@ fn test_empty() {
 }
 
 #[test]
+#[ignore]
 fn test_arg_overrides_stdin() {
     let (at, mut ucmd) = at_and_ucmd!();
     let input = "foobarfoobar";