gh-104533: Fix ctypes test_pointer_proto_missing_argtypes_error()

[vstinner]

Save/restore Py_GetVersion.argtypes, since Py_GetVersion is used in another test.

• Issue: Annotation-based syntax for ctypes structs #104533

[vstinner]

This change should fix the Refleaks buildbot: https://buildbot.python.org/#/builders/320/builds/4302

This buildbot runs test_ctypes 6x in a row to check for memory leaks. test_ctypes fails at the second run.

ERROR: test_wrap_dll_function_str_ann (test.test_ctypes.test_funcptr.CFuncPtrTestCase.test_wrap_dll_function_str_ann)
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Traceback (most recent call last):
  File "/home/buildbot-worker/cstratak-fedora-stable-x86_64/3.x.cstratak-fedora-stable-x86_64.refleak/build/Lib/test/test_ctypes/test_funcptr.py", line 156, in test_wrap_dll_function_str_ann
    version = wrap_str_ann.Py_GetVersion()
TypeError: this function takes at least 1 argument (0 given)