block: Remove unused aio_task_pool_empty

aio_task_pool_empty has been unused since it was added in
  6e9b225f73 ("block: introduce aio task pool")

Remove it.

Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
Message-Id: <20240917002007.330689-1-dave@treblig.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

block/aio_task.c

@@ -119,8 +119,3 @@ int aio_task_pool_status(AioTaskPool *pool)
 
     return pool->status;
 }
-
-bool aio_task_pool_empty(AioTaskPool *pool)
-{
-    return pool->busy_tasks == 0;
-}

include/block/aio_task.h

@@ -40,8 +40,6 @@ void aio_task_pool_free(AioTaskPool *);
 /* error code of failed task or 0 if all is OK */
 int aio_task_pool_status(AioTaskPool *pool);
 
-bool aio_task_pool_empty(AioTaskPool *pool);
-
 /* User provides filled @task, however task->pool will be set automatically */
 void coroutine_fn aio_task_pool_start_task(AioTaskPool *pool, AioTask *task);