fix unused import (#4163)

test/plugin/mock-collector/src/main/java/org/apache/skywalking/plugin/test/mockcollector/entity/RegistryItem.java

@@ -17,15 +17,12 @@
 package org.apache.skywalking.plugin.test.mockcollector.entity;
 
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 
-import org.apache.skywalking.apm.network.language.agent.SpanType;
-
 public class RegistryItem {
     /**
      * applicationCode, applicationId

test/plugin/mock-collector/src/main/java/org/apache/skywalking/plugin/test/mockcollector/entity/ValidateData.java

@@ -34,7 +34,7 @@ public class ValidateData {
         return segmentItem;
     }
 
-    public static void clearData(){
+    public static void clearData() {
         System.out.println("Clear Data");
         INSTANCE.segmentItem = new SegmentItems();
         INSTANCE.registryItem.getOperationNames().clear();