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

internal/builtins/int.go

@@ -16,20 +16,20 @@ func Int(args ...object.Object) object.Object {
 	}
 
 	switch arg := args[0].(type) {
-	case *object.Boolean:
+	case object.Boolean:
 		if arg.Value {
-			return &object.Integer{Value: 1}
+			return object.Integer{Value: 1}
 		}
-		return &object.Integer{Value: 0}
-	case *object.Integer:
+		return object.Integer{Value: 0}
+	case object.Integer:
 		return arg
-	case *object.String:
+	case object.String:
 		n, err := strconv.ParseInt(arg.Value, 10, 64)
 		if err != nil {
 			return newError("could not parse string to int: %s", err)
 		}
-		return &object.Integer{Value: n}
+		return object.Integer{Value: n}
 	default:
-		return &object.Integer{}
+		return object.Integer{}
 	}
 }