Implement equals/hashcode in BatchTestContextCustomizer

Resolves #3940

spring-batch-test/src/main/java/org/springframework/batch/test/context/BatchTestContextCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2018 the original author or authors.
+ * Copyright 2018-2021 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.
@@ -51,4 +51,14 @@ public class BatchTestContextCustomizer implements ContextCustomizer {
 				new RootBeanDefinition(JobRepositoryTestUtils.class));
 	}
 
+	@Override
+	public boolean equals(Object obj) {
+		return obj != null && getClass() == obj.getClass();
+	}
+
+	@Override
+	public int hashCode() {
+		return getClass().hashCode();
+	}
+
 }