Use ServletWrappingController for jolokia instead of Servlet

We get more control over the handling and in particular the registration
of the endpoint this way. It was practically impossible to disable the
AgentServlet bean when in a parent context of the management server
because of lifecyce issues - you don't know that the user wants a
separate management server until too late.

This approach also makes it possible to test with spring-test MVC
support.

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/MultipartAutoConfigurationTests.java

@@ -139,12 +139,13 @@ public class MultipartAutoConfigurationTests {
 	}
 
 	@Test
-	public void containerWithAutomatedMultipartTomcatConfiguration() {
+	public void containerWithAutomatedMultipartTomcatConfiguration() throws Exception {
 		this.context = new AnnotationConfigEmbeddedWebApplicationContext(
 				ContainerWithEverythingTomcat.class,
 				EmbeddedServletContainerAutoConfiguration.class,
 				DispatcherServletAutoConfiguration.class,
 				MultipartAutoConfiguration.class);
+		new RestTemplate().getForObject("http://localhost:8080/", String.class);
 		this.context.getBean(MultipartConfigElement.class);
 		assertSame(this.context.getBean(DispatcherServlet.class).getMultipartResolver(),
 				this.context.getBean(StandardServletMultipartResolver.class));