Confirm node construction cannot handle bad blocks.

This fixes 176.gcc.

ir/ana/irconsconfirm.c

@@ -529,6 +529,7 @@ void construct_confirms(ir_graph *irg)
 	assure_irg_properties(irg,
 		IR_GRAPH_PROPERTY_CONSISTENT_OUT_EDGES
 		| IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE
+		| IR_GRAPH_PROPERTY_NO_BADS
 		| IR_GRAPH_PROPERTY_NO_CRITICAL_EDGES);
 
 	assert(get_irg_pinned(irg) == op_pin_state_pinned &&