std.fs.Dir: fix updateFile() to flush the file before updating its times

AtomicFile.finish() calls flush() which renders any previous updateTimes() calls
useless. Regression introduced in f2a3ac7c05.

Closes #24927.

lib/std/fs/Dir.zig

@@ -2583,8 +2583,9 @@ pub fn updateFile(
         error.ReadFailed => return src_reader.err.?,
         error.WriteFailed => return atomic_file.file_writer.err.?,
     };
+    try atomic_file.flush();
     try atomic_file.file_writer.file.updateTimes(src_stat.atime, src_stat.mtime);
-    try atomic_file.finish();
+    try atomic_file.renameIntoPlace();
     return .stale;
 }