Fix StatementGeneratorTest

src/test/java/de/dhbw/horb/StatementGeneratorTest.java

@@ -27,6 +27,6 @@ public class StatementGeneratorTest
         DecafLexer lexer = new DecafLexer(input);
         CommonTokenStream tokens = new CommonTokenStream(lexer);
         DecafParser parser = new DecafParser(tokens);
-        return new StatementGenerator().visit(parser.stmt());
+        return parser.stmt().accept(new StatementGenerator());
     }
 }