Merge pull request #1193 from xyyz150/master

优化在JobThread尝试30次后销毁任务时，并发插入到triggerQueue中任务会失败的场景

xxl-job-core/src/main/java/com/xxl/job/core/thread/JobThread.java

@@ -165,7 +165,9 @@ public class JobThread extends Thread{
 
 				} else {
 					if (idleTimes > 30) {
-						XxlJobExecutor.removeJobThread(jobId, "excutor idel times over limit.");
+						if(triggerQueue ==null||triggerQueue.size()==0) {
+							XxlJobExecutor.removeJobThread(jobId, "excutor idel times over limit.");
+						}
 					}
 				}
 			} catch (Throwable e) {