Mark class as final

Author: eregon

src/main/java/org/truffleruby/parser/YARPTranslatorDriver.java

@@ -90,7 +90,7 @@
 import java.util.Arrays;
 import java.util.List;
 
-public class YARPTranslatorDriver {
+public final class YARPTranslatorDriver {
 
     /** May be null, see {@link ParserCache#parse} */
     private final RubyContext context;