I noticed this on bug 708499. It wouldn't have made us catch that issue (since we don't check for those kind of leaks on tinderbox), but it would have been nice to facilitate manual testing.
I've fixed this on both branches. This bug is to fix it on central. Patch coming right up.
Created attachment 582065 [details] [diff] [review]
enable XPConnect wstring test. v1
Attached a patch. Flagging khuey for rubberstamp.
Pushed to mozilla-inbound: http://hg.mozilla.org/integration/mozilla-inbound/rev/c17b09e6654f