Use correct method to test "purejson" library (fabienrenaud#49)

Author: darxriggs

src/test/java/com/github/fabienrenaud/jjb/JsonBenchmark.java

@@ -253,11 +253,11 @@ public void underscore_java() throws Exception {
             test(Library.UNDERSCORE_JAVA, BENCH.underscore_java());
         }
     }
-    
+
     @Test
     public void purejson() throws Exception {
         for (int i = 0; i < ITERATIONS; i++) {
-            test(Library.PUREJSON, BENCH.underscore_java());
+            test(Library.PUREJSON, BENCH.purejson());
         }
     }
 }