Europe’s economy saw modest growth in the April-June quarter even as the U.S. outperformed expectations, highlighting a persistent transatlantic growth gap. Germany, the leading European economy, remained in the dumps while hesitant consumers saved more rather than spending on new houses or cars. Gross domestic product, the total output of goods and services, rose 0.3% in the second quarter in the 20 countries that use the euro currency, according to official figures released Tuesday by...