add comments about not unlocking in test

Author: beepster4096

tests/pass/concurrency/windows_condvar_shared.rs

@@ -60,6 +60,8 @@ fn all_shared() {
             assert_ne!(r, 0);
 
             println!("exclusive waiter {i} reacquired lock");
+
+            // unlocking is unnecessary because the lock is never used again
         }));
     }
 
@@ -125,6 +127,8 @@ fn shared_sleep_and_exclusive_lock() {
             assert_ne!(r, 0);
 
             println!("shared waiter {i} reacquired lock");
+
+            // unlocking is unnecessary because the lock is never used again
         }));
     }