Implement optional pass parameter of for loop to be null when not defined

js/ast/ivprogParser.js

@@ -897,9 +897,6 @@ export class IVProgParser {
     const for_from = this.parseForFrom();
     const for_to = this.parseForTo();
     let maybePass = this.parseForPass();
-    if (maybePass == null) {
-      maybePass = new Expressions.IntLiteral(toInt(1));
-    }
     this.consumeNewLines();
     const commandsBlock = this.parseCommandBlock();
     this.popScope();