resourceutil: force filesystem access to resources when using py2exe

I don't know why it doesn't work, but it avoids this fatal error on startup:

    > hg debugshell
    Traceback (most recent call last):
      File "hg", line 58, in <module>
      File "mercurial\dispatch.pyc", line 143, in run
      File "mercurial\dispatch.pyc", line 232, in dispatch
      File "mercurial\dispatch.pyc", line 254, in _rundispatch
      File "mercurial\ui.pyc", line 316, in load
      File "mercurial\rcutil.pyc", line 98, in rccomponents
      File "mercurial\rcutil.pyc", line 68, in default_rc_resources
      File "mercurial\utils\resourceutil.pyc", line 102, in contents
      File "<frozen zipimport>", line 775, in contents
    AssertionError

I assume the py2 version of py2exe never hit this because `importlib.resources`
failed to import.

Differential Revision: https://phab.mercurial-scm.org/D12554

mercurial/utils/resourceutil.py

@@ -61,6 +61,10 b' try:'
     # Force loading of the resources module
     resources.open_binary  # pytype: disable=module-attr
 
+    # py2exe raises an AssertionError if uses importlib.resources
+    if getattr(sys, "frozen", None) in ("console_exe", "windows_exe"):
+        raise ImportError
+
 except (ImportError, AttributeError):
     # importlib.resources was not found (almost definitely because we're on a
     # Python version before 3.7)