test(locks): add comprehensive unit tests for spin_lock and rw_lock

- Test spin_lock basic operations and mutual exclusion
- Test spin_lock critical section protection
- Test spin_lock concurrent access and contention
- Test rw_lock write lock (exclusive access)
- Test rw_lock read lock (shared access)
- Test multiple concurrent readers
- Test writers have exclusive access
- Test readers and writers don't overlap
- Test various read-write patterns
- Test rapid lock/unlock operations
- Test mixed concurrent operations
- Test write lock blocks readers correctly

Author: mutouyun