sched_ext/selftests: Fix incorrect include guard comments

Fix two mismatched closing comments in header include guards:

- util.h: closing comment says __SCX_TEST_H__ but the guard is
  __SCX_TEST_UTIL_H__
- exit_test.h: closing comment has a spurious '#' character before
  the guard name

Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

tools/testing/selftests/sched_ext/exit_test.h

@@ -17,4 +17,4 @@ enum exit_test_case {
 	NUM_EXITS,
 };
 
-#endif  // # __EXIT_TEST_H__
+#endif  // __EXIT_TEST_H__

tools/testing/selftests/sched_ext/util.h

@@ -10,4 +10,4 @@
 long file_read_long(const char *path);
 int file_write_long(const char *path, long val);
 
-#endif // __SCX_TEST_H__
+#endif // __SCX_TEST_UTIL_H__