Ignore BackgroundPreinitializer in native images

BackgroundPreinitializer is not relevant in native images so it is
better to ignore it automatically in order to reduce the footprint
in such environment.

See gh-22392

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java

@@ -45,6 +45,7 @@ import org.springframework.http.converter.support.AllEncompassingFormHttpMessage
  * @author Phillip Webb
  * @author Andy Wilkinson
  * @author Artsiom Yudovin
+ * @author Sebastien Deleuze
  * @since 1.3.0
  */
 @Order(LoggingApplicationListener.DEFAULT_ORDER + 1)
@@ -67,6 +68,7 @@ public class BackgroundPreinitializer implements ApplicationListener<SpringAppli
 
 	static {
 		ENABLED = !Boolean.getBoolean(IGNORE_BACKGROUNDPREINITIALIZER_PROPERTY_NAME)
+				&& System.getProperty("org.graalvm.nativeimage.imagecode") == null
 				&& Runtime.getRuntime().availableProcessors() > 1;
 	}