[Groovy] Class RecursivenessTester

Test if a method call is recursive if called within a given method node. Handles static calls as well. Currently known simplifications:

• Does not check for method overloading or overridden methods
• Does not check for matching return types; even void and any object type are considered to be compatible
• Argument type matching could be more specific in case of static compilation
• Method names via a GString are never considered to be recursive