old_contents: (function(program, execJS) { execJS(program) })(function() { #{source}
  }, function(program) {
    var output;
    try {
      delete this.console;
      delete this.console;
      delete this.setTimeout;
      delete this.setInterval;
      delete this.clearTimeout;
      delete this.clearInterval;
      delete this.setImmediate;
      delete this.clearImmediate;
  
      result = program();
      if (typeof result == 'undefined' && result !== null) {
        print('["ok"]');
      } else {
        try {
          print(JSON.stringify(['ok', result]));
        } catch (err) {
          print(JSON.stringify(['err', '' + err, err.stack]));
        }
      }
    } catch (err) {
      print(JSON.stringify(['err', '' + err, err.stack]));
    }
  });
  
new_contents: (function(program, execJS) { execJS(program) })(function() { #{source}
  }, function(program) {
    var output;
    try {
      delete this.console;
      delete this.setTimeout;
      delete this.setInterval;
      delete this.clearTimeout;
      delete this.clearInterval;
      delete this.setImmediate;
      delete this.clearImmediate;
  
      result = program();
      if (typeof result == 'undefined' && result !== null) {
        print('["ok"]');
      } else {
        try {
          print(JSON.stringify(['ok', result]));
        } catch (err) {
          print(JSON.stringify(['err', '' + err, err.stack]));
        }
      }
    } catch (err) {
      print(JSON.stringify(['err', '' + err, err.stack]));
    }
  });
  
subject: Remove duplicate `delete this.console;`