enable test_io from CI

Author: youknowone

.github/workflows/ci.yaml

@@ -20,14 +20,12 @@ env:
   CARGO_ARGS_NO_SSL: --no-default-features --features stdlib,importlib,stdio,encodings,sqlite
   # Skip additional tests on Windows. They are checked on Linux and MacOS.
   # test_glob: many failing tests
-  # test_io: many failing tests
   # test_os: many failing tests
   # test_pathlib: panic by surrogate chars
   # test_posixpath: OSError: (22, 'The filename, directory name, or volume label syntax is incorrect. (os error 123)')
   # test_venv: couple of failing tests
   WINDOWS_SKIPS: >-
     test_glob
-    test_io
     test_os
     test_rlcompleter
     test_pathlib