Polish access modifiers for test classes

See gh-27736

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/SpringBootTestWithActiveProfilesAndEnvironmentPropertyTests.java

@@ -42,7 +42,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 @SpringBootTest
 @ActiveProfiles({ "test1", "test2" })
 @ContextConfiguration(loader = SpringBootTestWithActiveProfilesAndEnvironmentPropertyTests.Loader.class)
-public class SpringBootTestWithActiveProfilesAndEnvironmentPropertyTests {
+class SpringBootTestWithActiveProfilesAndEnvironmentPropertyTests {
 
 	@Autowired
 	private Environment environment;

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/SpringBootTestWithActiveProfilesAndSystemEnvironmentPropertyTests.java

@@ -44,7 +44,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 @SpringBootTest
 @ActiveProfiles({ "test1", "test2" })
 @ContextConfiguration(loader = SpringBootTestWithActiveProfilesAndSystemEnvironmentPropertyTests.Loader.class)
-public class SpringBootTestWithActiveProfilesAndSystemEnvironmentPropertyTests {
+class SpringBootTestWithActiveProfilesAndSystemEnvironmentPropertyTests {
 
 	@Autowired
 	private Environment environment;

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/web/reactive/server/WebTestClientContextCustomizerWithoutSupportedHttpClientTests.java

@@ -33,7 +33,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Andy Wilkinson
  */
 @ClassPathExclusions({ "reactor-netty*.jar", "jetty-client*.jar" })
-public class WebTestClientContextCustomizerWithoutSupportedHttpClientTests {
+class WebTestClientContextCustomizerWithoutSupportedHttpClientTests {
 
 	@Test
 	void createContextCustomizerWhenNoSupportedHttpClientIsAvailableShouldReturnNull() {

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/web/reactive/server/WebTestClientContextCustomizerWithoutWebfluxIntegrationTests.java

@@ -34,7 +34,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * @author Stephane Nicoll
  */
 @ClassPathExclusions("spring-webflux*.jar")
-public class WebTestClientContextCustomizerWithoutWebfluxIntegrationTests {
+class WebTestClientContextCustomizerWithoutWebfluxIntegrationTests {
 
 	@Test
 	void customizerIsNotCreatedWithoutWebClient() {