[SelectionDAG] Check any use of negation result before removal
2508ef01 fixed a bug about constant removal in negation. But after sanitizing check I found there's still some issue about it so it's reverted.
Temporary nodes will be removed if useless in negation. Before the removal, they'd be checked if any other nodes used it. So the removal was moved after getNode. However in rare cases the node to be removed is the same as result of getNode. We missed that and will be fixed by this patch.