Merge pull request #594 from morrme/lsp-remove-final

largest-series-product: remove "final" from class declaration

exercises/largest-series-product/src/test/java/LargestSeriesProductCalculatorTest.java

 
 import static org.junit.Assert.assertEquals;
 
-public final class LargestSeriesProductCalculatorTest {
+public class LargestSeriesProductCalculatorTest {
 
     /*
      * See https://github.com/junit-team/junit4/wiki/Rules for information on JUnit Rules in general and