Bugfix: If unblock failed and all devices in a group were blocked, task would be added to queue and waiting for cron to unblock (#686)

…sk would be added to queue and wait corn to unblock

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### Linked GitHub issue ID: #  

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Author: zhou9584

center/src/main/java/com/microsoft/hydralab/center/controller/TestTaskController.java

@@ -99,6 +99,8 @@ public Result<Object> runTestTask(@CurrentSecurityContext SysUser requestor,
                 }
                 testTaskService.checkTestTaskTeamConsistency(testTaskSpec);
             }
+            // unblock frozen devices
+            deviceAgentManagementService.unblockFrozenBlockedDevices();
             //if the queue is not empty, the task will be added to the queue directly
             if (testTaskService.isQueueEmpty()
                     || Task.RunnerType.APK_SCANNER.name().equals(testTaskSpec.runningType)

center/src/main/java/com/microsoft/hydralab/center/service/DeviceAgentManagementService.java

@@ -707,7 +707,6 @@ public List<AgentDeviceGroup> getAllAppiumAgents() {
 
     public JSONObject runTestTaskBySpec(TestTaskSpec testTaskSpec) {
         JSONObject result;
-        unblockFrozenBlockedDevices();
         if (Task.RunnerType.APPIUM_CROSS.name().equals(testTaskSpec.runningType)) {
             result = runAppiumTestTask(testTaskSpec);
         } else if (Task.RunnerType.T2C_JSON.name().equals(testTaskSpec.runningType)) {

center/src/main/java/com/microsoft/hydralab/center/service/TestTaskService.java

@@ -101,6 +101,8 @@ public void runTask() {
         }
         isRunning.set(true);
 
+        // unblock frozen devices
+        deviceAgentManagementService.unblockFrozenBlockedDevices();
         synchronized (taskQueue) {
             Iterator<TestTaskSpec> queueIterator = taskQueue.iterator();
             while (queueIterator.hasNext()) {