test_weak_ref fails for zed

[Corey Bryant]

murano.tests.unit.dsl.test_helpers.TestDSLHelpers.test_weak_ref
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Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/usr/lib/python3.10/unittest/mock.py", line 1369, in patched
    return func(*newargs, **newkeywargs)

      File "/home/corey/pkg/zed/upstream/murano/murano/tests/unit/dsl/test_helpers.py", line 268, in test_weak_ref
    self.assertEqual('weakref',

      File "/home/corey/pkg/zed/upstream/murano/.tox/py310/lib/python3.10/site-packages/testtools/testcase.py", line 393, in assertEqual
    self.assertThat(observed, matcher, message)

      File "/home/corey/pkg/zed/upstream/murano/.tox/py310/lib/python3.10/site-packages/testtools/testcase.py", line 480, in assertThat
    raise mismatch_error

    testtools.matchers._impl.MismatchError: 'weakref' != 'ReferenceType'

This was hit running 'tox -e py310' on the master branch (zed).