Fix object graph deletion in SimpleJobRepository#deleteJobExecution

Before this commit, SimpleJobRepository#deleteJobExecution
did not delete associated step executions as specified in the
contract of the method.

This commit fixes the implementation to delete the entire
object graph as specified.

Resolves #4249

spring-batch-core/src/main/java/org/springframework/batch/core/repository/support/SimpleJobRepository.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2022 the original author or authors.
+ * Copyright 2006-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -320,6 +320,9 @@ public class SimpleJobRepository implements JobRepository {
 	public void deleteJobExecution(JobExecution jobExecution) {
 		this.ecDao.deleteExecutionContext(jobExecution);
 		this.jobExecutionDao.deleteJobExecutionParameters(jobExecution);
+		for (StepExecution stepExecution : jobExecution.getStepExecutions()) {
+			deleteStepExecution(stepExecution);
+		}
 		this.jobExecutionDao.deleteJobExecution(jobExecution);
 	}