[mjsunit] Change assertThrows such that it can check the exception message.

test/mjsunit/mjsunit.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 358 matching lines @@
         eval(code);
       }
       threwException = false;
     } catch (e) {
       if (typeof type_opt === 'function') {
         assertInstanceof(e, type_opt);
       } else if (type_opt !== void 0) {
         failWithMessage("invalid use of assertThrows, maybe you want assertThrowsEquals");
       }
       if (arguments.length >= 3) {
-        assertEquals(e.type, cause_opt);
+        assertEquals(e.message, cause_opt);

[titzer, 2016/11/24 15:37:01]

What about checking both the type and the cause here?

[ahaas, 2016/11/28 09:47:53]

The JS standard defines only message, not type. I guess the check of e.type was
only introduced for the one regression test. I think it would make tests less
readable to check both type and message.

       }
       // Success.
       return;
     }
     failWithMessage("Did not throw exception");
   };
 
 
   assertThrowsEquals = function assertThrowsEquals(fun, val) {
     try {
@@ skipping 74 matching lines @@
     if (sync_opt === undefined) sync_opt = "";
     assertTrue(OptimizationStatus(fun, sync_opt) !== 1, name_opt);
   }
 
   assertOptimized = function assertOptimized(fun, sync_opt, name_opt) {
     if (sync_opt === undefined) sync_opt = "";
     assertTrue(OptimizationStatus(fun, sync_opt) !== 2, name_opt);
   }
 
 })();