Remove global condition waiter registry that deadlocks exception delivery

Co-authored-by: Bipin <bipinkrish4@gmail.com>

src/common/threads.h

@@ -77,7 +77,6 @@ public:
 	void Signal();
 	void SignalAll();
 
-	static void SignalThread(int thread_id);
 	static void SetWaitPollCallback(wait_poll_func_t callback);
 
 	KYTY_CLASS_NO_COPY(CondVar);