remove dead code (#5611)

apm-sniffer/apm-test-tools/src/main/java/org/apache/skywalking/apm/agent/core/context/MockContextSnapshot.java

@@ -18,9 +18,6 @@
 
 package org.apache.skywalking.apm.agent.core.context;
 
-import java.util.ArrayList;
-import java.util.List;
-import org.apache.skywalking.apm.agent.core.context.ids.DistributedTraceId;
 import org.apache.skywalking.apm.agent.core.context.ids.NewDistributedTraceId;
 
 public enum MockContextSnapshot {
@@ -29,11 +26,14 @@ public enum MockContextSnapshot {
     private ContextSnapshot contextSnapshot;
 
     MockContextSnapshot() {
-        List<DistributedTraceId> distributedTraceIds = new ArrayList<DistributedTraceId>();
-        distributedTraceIds.add(new NewDistributedTraceId());
-
         contextSnapshot = new ContextSnapshot(
-            "1, 2, 3", 1, new NewDistributedTraceId(), "/for-test-entryOperationName", new CorrelationContext(), new ExtensionContext());
+            "1, 2, 3",
+            1,
+            new NewDistributedTraceId(),
+            "/for-test-entryOperationName",
+            new CorrelationContext(),
+            new ExtensionContext()
+        );
     }
 
     public ContextSnapshot mockContextSnapshot() {