code: Node tryFoldWhile(Node n) {
      checkArgument(n.isWhile());
      Node cond = NodeUtil.getConditionExpression(n);
      if (NodeUtil.getPureBooleanValue(cond) != TernaryValue.FALSE) {
        return n;
      }
      NodeUtil.redeclareVarsInsideBranch(n);
      reportChangeToEnclosingScope(n.getParent());
      NodeUtil.removeChild(n.getParent(), n);
  
      return null;
    }
docs: Removes WHILEs that always evaluate to false.