We used to store "generic" (all-Object) versions of invokers and constructors in a weak hash map (reasoning was that they're rare, so we shouldn't pay the price of a field in RecompilableScriptFunctionData).

Well, turns out we have to, otherwise we get a significant performance hit. I reduced the storage hit by introducing a holder class (GenericInvokers) for the two fields, and only have RecompilableScriptFunctionData reference the holder object. The heuristics here is again that in most cases, functions will not be using the generic invokers.