Collect garbage before serializing heap in test-serialize

BUG=none
TEST=nosnap bots with i18n enabled are happy
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/24196004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16826 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/cctest/test-serialize.cc

@@ -256,8 +256,10 @@ static void Serialize() {
     v8::HandleScope scope(isolate);
     v8::Context::New(isolate);
   }
-  WriteToFile(reinterpret_cast<Isolate*>(isolate),
-              FLAG_testing_serialization_file);
+
+  Isolate* internal_isolate = CcTest::i_isolate();
+  internal_isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags, "serialize");
+  WriteToFile(internal_isolate, FLAG_testing_serialization_file);
 }