Consistent whitespace after imports

Update code to have a consistent number of new-line characters after
import statements.

spring-web/src/main/java/org/springframework/web/context/request/async/AsyncWebRequest.java

@@ -18,7 +18,6 @@ package org.springframework.web.context.request.async;
 
 import org.springframework.web.context.request.NativeWebRequest;
 
-
 /**
  * Extends {@link NativeWebRequest} with methods for asynchronous request processing.
  *

spring-web/src/main/java/org/springframework/web/context/support/ServletContextPropertyPlaceholderConfigurer.java

@@ -23,7 +23,6 @@ import javax.servlet.ServletContext;
 import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
 import org.springframework.web.context.ServletContextAware;
 
-
 /**
  * Subclass of {@link PropertyPlaceholderConfigurer} that resolves placeholders as
  * ServletContext init parameters (that is, {@code web.xml} context-param

spring-web/src/main/java/org/springframework/web/method/annotation/ExceptionHandlerMethodResolver.java

@@ -32,7 +32,6 @@ import org.springframework.util.ReflectionUtils.MethodFilter;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.method.HandlerMethodSelector;
 
-
 /**
  * Discovers annotated exception handling methods in a given class type, including all
  * super types, and helps to resolve an Exception to a method that can handle it. The