Update SkyWalkingAgent.java

Fix bug.

apm-sniffer/apm-agent/src/main/java/org/skywalking/apm/agent/SkyWalkingAgent.java

@@ -61,7 +61,7 @@ public class SkyWalkingAgent {
                     DynamicType.Builder<?> newBuilder = builder;
                     EnhanceContext context = new EnhanceContext();
                     for (AbstractClassEnhancePluginDefine define : pluginDefines) {
-                        DynamicType.Builder<?> possibleNewBuilder = define.define(typeDescription.getTypeName(), builder, classLoader, context);
+                        DynamicType.Builder<?> possibleNewBuilder = define.define(typeDescription.getTypeName(), newBuilder, classLoader, context);
                         if (possibleNewBuilder != null) {
                             newBuilder = possibleNewBuilder;
                         }