Fix compile

dubbo-common/src/test/java/org/apache/dubbo/common/config/configcenter/AbstractDynamicConfigurationTest.java

@@ -104,7 +104,7 @@ protected boolean doRemoveConfig(String key, String group) {
             }
         };
 
-        ThreadPoolExecutor threadPoolExecutor = configuration.getWorkersThreadPool();
+        ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) configuration.getWorkersThreadPool();
         ThreadFactory threadFactory = threadPoolExecutor.getThreadFactory();
 
         Thread thread = threadFactory.newThread(() -> {});