Revert "Remove cargo-fmt and rustfmt-bin from self_tests()"

This reverts commit 93c349a6c1.

rustfmt-core/tests/lib.rs

@@ -211,7 +211,12 @@ fn idempotence_tests() {
 #[test]
 fn self_tests() {
     let mut files = get_test_files(Path::new("tests"), false);
-    let bin_directories = vec!["git-rustfmt", "rustfmt-format-diff"];
+    let bin_directories = vec![
+        "cargo-fmt",
+        "git-rustfmt",
+        "rustfmt-bin",
+        "rustfmt-format-diff",
+    ];
     for dir in bin_directories {
         let mut path = PathBuf::from("..");
         path.push(dir);