graph-lock: remove AioContext locking

Stop acquiring/releasing the AioContext lock in
bdrv_graph_wrlock()/bdrv_graph_unlock() since the lock no longer has any
effect.

The distinction between bdrv_graph_wrunlock() and
bdrv_graph_wrunlock_ctx() becomes meaningless and they can be collapsed
into one function.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231205182011.1976568-6-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/blkverify.c b/block/blkverify.c
index 9b17c46..ec45d83 100644
--- a/block/blkverify.c
+++ b/block/blkverify.c
@@ -151,10 +151,10 @@
 {
     BDRVBlkverifyState *s = bs->opaque;
 
-    bdrv_graph_wrlock(NULL);
+    bdrv_graph_wrlock();
     bdrv_unref_child(bs, s->test_file);
     s->test_file = NULL;
-    bdrv_graph_wrunlock(NULL);
+    bdrv_graph_wrunlock();
 }
 
 static int64_t coroutine_fn GRAPH_RDLOCK