Java: Add up/downgrade scripts

Author: igfoo

java/downgrades/1fd1afa7862b82955785edd29820054ab6c9ec81/erasure.ql

@@ -0,0 +1,9 @@
+class ClassOrInterface extends @classorinterface {
+  string toString() { none() }
+}
+
+from ClassOrInterface x, ClassOrInterface y
+where
+  classes_or_interfaces(x, _, _, y) and
+  x != y
+select x, y