Revert "Clear corresponding irg property when creating Bads."

This reverts commit 3d1d2c43.

Creating a Bad node does not imply that it has users or is reachable
within an irg. While clearing the property is certainly correct as a
conservative approximation, it should not be necessary.

scripts/ir_spec.py

@@ -176,7 +176,6 @@ class Bad:
 	attr_struct   = "bad_attr"
 	init = '''
 	res->attr.bad.irg.irg = irg;
-	clear_irg_properties(irg, IR_GRAPH_PROPERTY_NO_BADS);
 	'''
 
 @op