Fix VM memory allocation optimizations by reducing what we allocate on the heap

internal/builtins/abs.go

@@ -15,10 +15,10 @@ func Abs(args ...object.Object) object.Object {
 		return newError(err.Error())
 	}
 
-	i := args[0].(*object.Integer)
+	i := args[0].(object.Integer)
 	value := i.Value
 	if value < 0 {
 		value = value * -1
 	}
-	return &object.Integer{Value: value}
+	return object.Integer{Value: value}
 }