[JAVA-8355] Move article code to spring-testing-2 module

testing-modules/spring-testing/src/main/java/com/baeldung/testexecutionlisteners/AdditionService.java

@@ -1,10 +0,0 @@
-package com.baeldung.testexecutionlisteners;
-
-import org.springframework.stereotype.Service;
-
-@Service
-public class AdditionService {
-    public int add(int a, int b) {
-        return a + b;
-    }
-}