Defer creating logger in StandardWebSocketHandlerAdapter to instantiation time

Closes gh-25427

(cherry picked from commit 64f4703445)

spring-websocket/src/main/java/org/springframework/web/socket/adapter/standard/StandardWebSocketHandlerAdapter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -41,7 +41,7 @@ import org.springframework.web.socket.handler.ExceptionWebSocketHandlerDecorator
  */
 public class StandardWebSocketHandlerAdapter extends Endpoint {
 
-	private static final Log logger = LogFactory.getLog(StandardWebSocketHandlerAdapter.class);
+	private final Log logger = LogFactory.getLog(StandardWebSocketHandlerAdapter.class);
 
 	private final WebSocketHandler handler;