Consistent handling of InterruptedException

Issue: SPR-16479

spring-test/src/main/java/org/springframework/test/web/servlet/DefaultMvcResult.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -143,6 +143,7 @@ class DefaultMvcResult implements MvcResult {
 					Thread.sleep(100);
 				}
 				catch (InterruptedException ex) {
+					Thread.currentThread().interrupt();
 					throw new IllegalStateException("Interrupted while waiting for " +
 							"async result to be set for handler [" + this.handler + "]", ex);
 				}