Fix return values for Harmony map and set operations.

test/mjsunit/harmony/collections.js

 // Copyright 2011 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 47 matching lines @@
   assertThrows(function () { m.set(0, 0) }, TypeError);
   assertThrows(function () { m.get('a-key') }, TypeError);
   assertThrows(function () { m.set('a-key', 0) }, TypeError);
 }
 TestInvalidCalls(new WeakMap);
 
 
 // Test expected behavior for Sets
 function TestSet(set, key) {
   assertFalse(set.has(key));
-  set.add(key);
+  assertSame(undefined, set.add(key));
   assertTrue(set.has(key));
-  set.delete(key);
+  assertTrue(set.delete(key));
+  assertFalse(set.has(key));
+  assertFalse(set.delete(key));
   assertFalse(set.has(key));
 }
 function TestSetBehavior(set) {
   for (var i = 0; i < 20; i++) {
     TestSet(set, new Object);
     TestSet(set, i);
     TestSet(set, i / 100);
     TestSet(set, 'key-' + i);
   }
   var keys = [ +0, -0, +Infinity, -Infinity, true, false, null, undefined ];
   for (var i = 0; i < keys.length; i++) {
     TestSet(set, keys[i]);
   }
 }
 TestSetBehavior(new Set);
 
 
 // Test expected mapping behavior for Maps and WeakMaps
 function TestMapping(map, key, value) {
-  map.set(key, value);
+  assertSame(undefined, map.set(key, value));
   assertSame(value, map.get(key));
 }
 function TestMapBehavior1(m) {
   TestMapping(m, new Object, 23);
   TestMapping(m, new Object, 'the-value');
   TestMapping(m, new Object, new Object);
 }
 TestMapBehavior1(new Map);
 TestMapBehavior1(new WeakMap);
 
@@ skipping 204 matching lines @@
     }
   }
 }
 TestBogusReceivers(bogusReceiversTestSet);
 
 
 // Stress Test
 // There is a proposed stress-test available at the es-discuss mailing list
 // which cannot be reasonably automated.  Check it out by hand if you like:
 // https://mail.mozilla.org/pipermail/es-discuss/2011-May/014096.html