Use the dataSource instead of getDataSource() to avoid connection leak

Author: 1996fanrui

flink-autoscaler-plugin-jdbc/src/test/java/org/apache/flink/autoscaler/jdbc/testutils/databases/postgres/PostgreSQLExtension.java

@@ -71,7 +71,7 @@ public void afterAll(ExtensionContext extensionContext) {
     @Override
     public void afterEach(ExtensionContext extensionContext) throws Exception {
         try (var dataSource = getDataSource();
-                var conn = getDataSource().getConnection();
+                var conn = dataSource.getConnection();
                 var st = conn.createStatement()) {
             for (var tableName : TABLES) {
                 st.executeUpdate(String.format("DELETE from %s", tableName));