Still missing _testinternalcapi module for Python3.9rc2
like https://bugs.python.org/issue36635

C:\Users\Admin>c:\python39\python.exe -m test test_deque
0:00:00 Run tests sequentially
0:00:00 [1/1] test_deque
test test_deque failed -- Traceback (most recent call last):
  File "c:\python39\lib\test\test_deque.py", line 781, in test_sizeof
    check(deque(), basesize + blocksize)
  File "c:\python39\lib\test\support\__init__.py", line 1484, in check_sizeof
    import _testinternalcapi
ModuleNotFoundError: No module named '_testinternalcapi'

test_deque failed

== Tests result: FAILURE ==

1 test failed:
    test_deque

Total duration: 1.1 sec
Tests result: FAILURE