Add missing license header

src/test/groovy/transform/stc/Pojo11451.java

@@ -1,3 +1,21 @@
+/*
+ *  Licensed to the Apache Software Foundation (ASF) under one
+ *  or more contributor license agreements. See the NOTICE file
+ *  distributed with this work for additional information
+ *  regarding copyright ownership. The ASF licenses this file
+ *  to you under the Apache License, Version 2.0 (the
+ *  "License"); you may not use this file except in compliance
+ *  with the License. You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing,
+ *  software distributed under the License is distributed on an
+ *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ *  KIND, either express or implied. See the License for the
+ *  specific language governing permissions and limitations
+ *  under the License.
+ */
 package groovy.transform.stc;
 
 import java.util.UUID;