Kotlin: Implement JvmOverloads annotation

This generates functions that omit parameters with default values, rightmost first, such that Java can achieve a similar experience to Kotlin (which represents calls internally as if the default was supplied explicitly, and/or uses a $default method that supplies the needed arguments).

A complication: combining JvmOverloads with JvmStatic means that both the companion object and the surrounding class get overloads.

java/ql/lib/semmle/code/java/Element.qll

@@ -63,6 +63,8 @@ class Element extends @element, Top {
       i = 7 and result = "Setter for a Kotlin delegated property"
       or
       i = 8 and result = "Proxy static method for a @JvmStatic-annotated function or property"
+      or
+      i = 9 and result = "Forwarder for a @JvmOverloads-annotated function"
     )
   }
 }