Remove 2 Boot substitutions

Thanks to spring-projects/spring-boot#22093 which brings support of
spring.xml.ignore flag natively to Spring Boot.

See spring-atticgh-138

Author: sdeleuze

spring-graalvm-native-configuration/src/main/resources/initialization.json

@@ -109,6 +109,7 @@
   // Spring Boot
   {"class": "org.springframework.boot.CommandLineRunner"},
   {"class": "org.springframework.boot.validation.MessageInterpolatorFactory"},
+  {"class": "org.springframework.boot.BeanDefinitionLoader"},
 
   // Tomcat, to avoid XML parsers and crypto classes
   {"class": "org.apache.catalina.servlets.DefaultServlet" },