Simplify if statements and replace try-finally with try-with-resources

Closes gh-23445

spring-jdbc/src/main/java/org/springframework/jdbc/datasource/DataSourceTransactionManager.java

@@ -408,13 +408,9 @@ public class DataSourceTransactionManager extends AbstractPlatformTransactionMan
 			throws SQLException {
 
 		if (isEnforceReadOnly() && definition.isReadOnly()) {
-			Statement stmt = con.createStatement();
-			try {
+			try (Statement stmt = con.createStatement()) {
 				stmt.executeUpdate("SET TRANSACTION READ ONLY");
 			}
-			finally {
-				stmt.close();
-			}
 		}
 	}