CompositeIndex profileSearch test unstable on Mac

[mauritsvanrees]

Similar to issue #140.

In the Zope gh-actions it [failed in a PR on 3.7]https://github.com/zopefoundation/Zope/actions/runs/3689677356/jobs/6245894691#step:6:461):

Failure in test testPerformance (Products.PluginIndexes.CompositeIndex.tests.testCompositeIndex.CompositeIndexPerformanceTest)
Traceback (most recent call last):
  File "/Users/runner/hostedtoolcache/Python/3.7.15/x64/lib/python3.7/unittest/case.py", line 59, in testPartExecutor
    yield
  File "/Users/runner/hostedtoolcache/Python/3.7.15/x64/lib/python3.7/unittest/case.py", line 628, in run
    testMethod()
  File "/Users/runner/work/Zope/Zope/.tox/py37/eggs/Products.ZCatalog-6.4-py3.7.egg/Products/PluginIndexes/CompositeIndex/tests/testCompositeIndex.py", line 322, in testPerformance
    profileSearch(query, verbose=True)
  File "/Users/runner/work/Zope/Zope/.tox/py37/eggs/Products.ZCatalog-6.4-py3.7.egg/Products/PluginIndexes/CompositeIndex/tests/testCompositeIndex.py", line 290, in profileSearch
    (duration2, duration1, query))
  File "/Users/runner/hostedtoolcache/Python/3.7.15/x64/lib/python3.7/unittest/case.py", line 1239, in assertLess
    self.fail(self._formatMessage(msg, standardMsg))
  File "/Users/runner/hostedtoolcache/Python/3.7.15/x64/lib/python3.7/unittest/case.py", line 693, in fail
    raise self.failureException(msg)
AssertionError: 2.217578887939453 not less than 1.226186752319336 : (5.543947219848633, 1.226186752319336, {'portal_type': {'query': 'Document'}, 'review_state': {'query': 'pending'}, 'is_default_page': {'query': True}, 'subject': {'query': ['subject_1', 'subject_3'], 'operator': 'and'}})

A second run passed, so I merged the PR. Then on master the Mac 3.9 test failed:

Failure in test testPerformance (Products.PluginIndexes.CompositeIndex.tests.testCompositeIndex.CompositeIndexPerformanceTest)
Traceback (most recent call last):
  File "/Users/runner/hostedtoolcache/Python/3.9.14/x64/lib/python3.9/unittest/case.py", line 59, in testPartExecutor
    yield
  File "/Users/runner/hostedtoolcache/Python/3.9.14/x64/lib/python3.9/unittest/case.py", line 592, in run
    self._callTestMethod(testMethod)
  File "/Users/runner/hostedtoolcache/Python/3.9.14/x64/lib/python3.9/unittest/case.py", line 550, in _callTestMethod
    method()
  File "/Users/runner/work/Zope/Zope/.tox/py39/eggs/Products.ZCatalog-6.4-py3.9.egg/Products/PluginIndexes/CompositeIndex/tests/testCompositeIndex.py", line 322, in testPerformance
    profileSearch(query, verbose=True)
  File "/Users/runner/work/Zope/Zope/.tox/py39/eggs/Products.ZCatalog-6.4-py3.9.egg/Products/PluginIndexes/CompositeIndex/tests/testCompositeIndex.py", line 287, in profileSearch
    self.assertLess(
  File "/Users/runner/hostedtoolcache/Python/3.9.14/x64/lib/python3.9/unittest/case.py", line 1223, in assertLess
    self.fail(self._formatMessage(msg, standardMsg))
  File "/Users/runner/hostedtoolcache/Python/3.9.14/x64/lib/python3.9/unittest/case.py", line 676, in fail
    raise self.failureException(msg)
AssertionError: 1.2979507446289062 not less than 0.3399848937988281 : (3.2448768615722656, 0.3399848937988281, {'portal_type': {'query': 'Document'}, 'is_default_page': {'query': True}})

It fails in this test.