Check that BPP and BFPP bean methods won't cause eager initialization

Closes gh-35164

spring-boot-project/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/autoconfigure/AbstractDevToolsDataSourceAutoConfigurationTests.java

@@ -151,7 +151,7 @@ abstract class AbstractDevToolsDataSourceAutoConfigurationTests {
 	static class DataSourceSpyConfiguration {
 
 		@Bean
-		DataSourceSpyBeanPostProcessor dataSourceSpyBeanPostProcessor() {
+		static DataSourceSpyBeanPostProcessor dataSourceSpyBeanPostProcessor() {
 			return new DataSourceSpyBeanPostProcessor();
 		}