Crash in tst_QObjectRace::disconnectRace2()

The Coin test run failed to parse the generated XML because it ended:

  <TestFunction name="disconnectRace">
    <Incident type="pass" file="" line="0" />
    <Duration msecs="6014.95"/>
  </TestFunction>
  <TestFunction name="disconnectRace2">

It would appear a test of raciness successfully caught a bug.
The test is in qtbase/tests/auto/other/qobjectrace/tst_qobjectrace.cpp; it was added by commit 71b4d4f150bc3c904a5aceec37513ddc3cd1c150.
Apparently QObject: attempt to fix a deadlock introduced by an earlier fix was not entirely successful