Adapt tests after Servlet.fn added to Spring Framework

Since Servlet.fn support has been added in Spring Framework, new
infrastructure beans (like `HandlerAdapter` and `HandlerMapping`) have
been added.

This commit adapts the Spring MVC auto-configuration tests to reflect
those changes.

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfigurationTests.java

@@ -137,7 +137,7 @@ public class WebMvcAutoConfigurationTests {
 	@Test
 	public void handlerAdaptersCreated() {
 		this.contextRunner.run((context) -> {
-			assertThat(context).getBeans(HandlerAdapter.class).hasSize(3);
+			assertThat(context).getBeans(HandlerAdapter.class).hasSize(4);
 			assertThat(context.getBean(RequestMappingHandlerAdapter.class)
 					.getMessageConverters()).isNotEmpty().isEqualTo(
 							context.getBean(HttpMessageConverters.class).getConverters());
@@ -147,7 +147,7 @@ public class WebMvcAutoConfigurationTests {
 	@Test
 	public void handlerMappingsCreated() {
 		this.contextRunner.run((context) -> assertThat(context)
-				.getBeans(HandlerMapping.class).hasSize(5));
+				.getBeans(HandlerMapping.class).hasSize(6));
 	}
 
 	@Test