Revert packaging changes of performance module.

...and remove duplicate properties entry.

See: #3309

spring-data-jpa-performance/pom.xml

@@ -7,7 +7,7 @@
 
 	<artifactId>spring-data-jpa-performance</artifactId>
 
-	<packaging>pom</packaging>
+	<packaging>jar</packaging>
 
 	<name>Spring Data JPA - Performance</name>
 	<description>Benchmark build for Spring Data JPA</description>

spring-data-jpa-performance/src/test/java/org/springframework/data/jpa/repository/RepositoryFinderTests.java

@@ -106,7 +106,6 @@ public class RepositoryFinderTests {
 			Map<String, String> properties = new HashMap<>();
 			properties.put("jakarta.persistence.jdbc.url", "jdbc:h2:mem:test");
 			properties.put("hibernate.dialect", "org.hibernate.dialect.H2Dialect");
-			properties.put("hibernate.dialect", "org.hibernate.dialect.H2Dialect");
 			properties.put("hibernate.hbm2ddl.auto", "update");
 			EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("benchmark", properties);