du: do not panic on a non-UTF-8 name in the --exclude check

The regular (non-safe) traversal — used with `-L`/`--dereference`, and always on
non-Linux — matched `--exclude` patterns against
`entry.file_name().into_string().unwrap()`, which aborts on any non-UTF-8 entry
name. Use `to_string_lossy()` instead, matching the sibling path check on the
same line, so a non-UTF-8 name is handled gracefully like GNU.

Author: leeewee

src/uu/du/src/du.rs

@@ -653,7 +653,7 @@ fn du_regular(
                                 // if we have 'du foo' but search to exclude 'foo/bar'
                                 // we need the full path
                                 if pattern.matches(&this_stat.path.to_string_lossy())
-                                    || pattern.matches(&entry.file_name().into_string().unwrap())
+                                    || pattern.matches(&entry.file_name().to_string_lossy())
                                 {
                                     // if the directory is ignored, leave early
                                     if options.verbose {

tests/by-util/test_du.rs

@@ -1364,6 +1364,21 @@ fn test_du_exclude() {
         .stdout_contains("'subdir' ignored");
 }
 
+#[test]
+#[cfg(unix)]
+fn test_du_exclude_non_utf8_name() {
+    use std::ffi::OsStr;
+    use std::os::unix::ffi::OsStrExt;
+
+    let ts = TestScenario::new(util_name!());
+    let at = &ts.fixtures;
+
+    at.mkdir("d");
+    at.mkdir(OsStr::from_bytes(b"d/\xff\xfesub"));
+
+    ts.ucmd().args(&["-L", "--exclude=zzz", "d"]).succeeds();
+}
+
 #[test]
 // Disable on Windows because we are looking for /
 // And the tests would be more complex if we have to support \ too