Fix class init configuration at main class level

Closes gh-1660

Author: sdeleuze

spring-aot/src/main/java/org/springframework/aot/nativex/ConfigurationContributor.java

@@ -77,7 +77,7 @@ public void contribute(BuildContext context, AotOptions aotOptions) {
 		context.describeProxies(proxies -> proxies.merge(configurationCollector.getProxyDescriptors()));
 		context.describeSerialization(serial -> serial.merge(configurationCollector.getSerializationDescriptor()));
 		context.describeJNIReflection(jniReflect -> jniReflect.merge(configurationCollector.getJNIReflectionDescriptor()));
-		context.describeInitialization(init -> init.merge(configurationCollector.getInitializationDescriptor()));
+		context.describeInitialization(init -> init.mergeTo(configurationCollector.getInitializationDescriptor()));
 		context.getOptions().forEach(configurationCollector::addOption);
 		String mainClass = getMainClass(context);
 		if (mainClass != null) {

spring-aot/src/main/java/org/springframework/nativex/domain/init/InitializationDescriptor.java

@@ -127,4 +127,11 @@ public void merge(InitializationDescriptor initializationDescriptor) {
 		this.runtimePackages.addAll(initializationDescriptor.getRuntimePackages());
 	}
 
+	public void mergeTo(InitializationDescriptor initializationDescriptor) {
+		initializationDescriptor.getBuildtimeClasses().addAll(this.buildtimeClasses);
+		initializationDescriptor.getBuildtimePackages().addAll(this.buildtimePackages);
+		initializationDescriptor.getRuntimeClasses().addAll(this.runtimeClasses);
+		initializationDescriptor.getRuntimePackages().addAll(this.runtimePackages);
+	}
+
 }