test: fix tmq case possibly fails

tests/system-test/7-tmq/subscribeDb1.py

@@ -442,7 +442,7 @@ class TDTestCase:
         showRow   = 1
         self.startTmqSimProcess(buildPath,cfgPath,pollDelay,parameterDict["dbName"],showMsg, showRow)
 
-        time.sleep(3)
+        time.sleep(6)
         tdLog.info("pkill consume processor")
         if (platform.system().lower() == 'windows'):
             os.system("TASKKILL /F /IM tmq_sim.exe")