C#: Add upgrade script.

Author: michaelnebel

csharp/ql/lib/upgrades/c9ee11bd1ee96e925a35cedff000be924634447f/compiler_generated.ql

@@ -0,0 +1,7 @@
+class Element extends @element {
+  Element() { expr_compiler_generated(this) or compiler_generated(this) }
+
+  string toString() { none() }
+}
+
+select any(Element e)