8271094: runtime/duplAttributes/DuplAttributesTest.java doesn't check…

… exit code

Reviewed-by: jiefu, dholmes

test/hotspot/jtreg/runtime/duplAttributes/DuplAttributesTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2014, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -44,6 +44,7 @@ public static void runTest(String test, String result) throws Throwable {
         ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(test);
         OutputAnalyzer output = new OutputAnalyzer(pb.start());
         output.shouldContain("java.lang.ClassFormatError: Multiple " + result);
+        output.shouldNotHaveExitValue(0);
     }
 
     public static void main(String args[]) throws Throwable {