Java: Add up/downgrade scripts

Author: igfoo

java/downgrades/876cabc76c5c83912271db331481f8cba2749643/fields.ql

@@ -0,0 +1,15 @@
+class Field extends @field {
+  string toString() { none() }
+}
+
+class Type extends @type {
+  string toString() { none() }
+}
+
+class RefType extends @reftype {
+  string toString() { none() }
+}
+
+from Field f, string name, Type t, RefType parent
+where fields(f, name, t, parent)
+select f, name, t, parent, f