ffi/com: faster when calling methods on many objects of same type
ffi/com: faster when calling methods on many objects of same type

Move the method-type cache to the type-info object, instead of
the instance.

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket