Update Test.java (#407)

Use uppercase L to declare variables

testcase/src/main/java/com/alibaba/arthas/Test.java

@@ -43,7 +43,7 @@ public class Test {
             list.get(random).setName(null);
             test(list);
             list.get(random).setName(name);
-            Thread.sleep(1000l);
+            Thread.sleep(1000L);
         }
     }