Do not commit response on access to content

MockHttpServletResponse no longer calls flushBuffer on calls to
getContentAsByteArray and getContentAsString. The flushing doesn't
actually do anything useful but does commit the response leading to
unexpected side effects.

Issue: SPR-16430

Author: rstoyanchev

spring-test/src/main/java/org/springframework/mock/web/MockHttpServletResponse.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.
@@ -199,12 +199,10 @@ public PrintWriter getWriter() throws UnsupportedEncodingException {
 	}
 
 	public byte[] getContentAsByteArray() {
-		flushBuffer();
 		return this.content.toByteArray();
 	}
 
 	public String getContentAsString() throws UnsupportedEncodingException {
-		flushBuffer();
 		return (this.characterEncoding != null ?
 				this.content.toString(this.characterEncoding) : this.content.toString());
 	}

spring-web/src/test/java/org/springframework/mock/web/test/MockHttpServletResponse.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.
@@ -192,12 +192,10 @@ public PrintWriter getWriter() throws UnsupportedEncodingException {
 	}
 
 	public byte[] getContentAsByteArray() {
-		flushBuffer();
 		return this.content.toByteArray();
 	}
 
 	public String getContentAsString() throws UnsupportedEncodingException {
-		flushBuffer();
 		return (this.characterEncoding != null ?
 				this.content.toString(this.characterEncoding) : this.content.toString());
 	}