tests: remove old cleanup handler for Windows subprocess (#8508)

tests/__init__.py

@@ -1,41 +1,13 @@
 import os
-import sys
 
 # Increasing fd ulimit for tests
 if os.name == "nt":
-    import subprocess
-
     try:
         import win32file  # pylint: disable=import-error
     except ImportError:
         pass
     else:
         win32file._setmaxstdio(4096)
-
-    # Workaround for two bugs:
-    #
-    # 1) gitpython-developers/GitPython#546
-    # GitPython leaves git cat-file --batch/--batch-check processes that are
-    # not cleaned up correctly, so Popen._active list has their defunct
-    # process handles, that it is not able to cleanup because of bug 2)
-    #
-    # 2) https://bugs.python.org/issue37380
-    # subprocess.Popen._internal_poll on windows is getting
-    #
-    # 	OSError: [WinError 6] The handle is invalid
-    #
-    # exception, which it doesn't ignore and so Popen is not able to cleanup
-    # old processes and that prevents it from creating any new processes at
-    # all, which results in our tests failing whenever they try to use Popen.
-    # This patch was released in 3.9.0 and backported to some earlier
-    # versions.
-    if sys.version_info < (3, 9, 0):
-
-        def noop():
-            pass
-
-        subprocess._cleanup = noop
-        subprocess._active = None
 else:
     import resource  # pylint: disable=import-error