amberc.js: always evaluate callback in async_map
amberc.js: always evaluate callback in async_map

even if array is empty

amber-smalltalk/amber,matthias-springer/amber-athens,amber-smalltalk/amber,amber-smalltalk/amber,adrian-castravete/amber,matthias-springer/amber-athens,adrian-castravete/amber,matthias-springer/amber-athens,adrian-castravete/amber