Modify NewSecondWorker case problem

Describe: There is a problem with NewSecondWorker case, missing variable
definition.

issue:https://gitee.com/openharmony/xts_acts/issues/I51JZ2Signed-off-by: Nyqhan <hanyuqing2@huawei.com>

compileruntime/worker_lib_standard/src/main/js/default/workers/worker_009.js

@@ -17,6 +17,7 @@ import worker from "@ohos.worker"
 const parentPort = worker.parentPort;
 
 var ss = undefined;
+var flag = false;
 
 parentPort.onmessage = function(e) {
   let data = e.data;