fmt: change test to ignore and fix test output

- fix test to get same result as GNU fmt

tests/by-util/test_fmt.rs

@@ -44,13 +44,14 @@ fn test_fmt_width_too_big() {
     }
 }
 
+#[ignore]
 #[test]
 fn test_fmt_goal() {
     for param in ["-g", "--goal"] {
         new_ucmd!()
             .args(&["one-word-per-line.txt", param, "7"])
             .succeeds()
-            .stdout_is("this is\na file\nwith one\nword per\nline\n");
+            .stdout_is("this is a\nfile with one\nword per line\n");
     }
 }