pythongh-149879: Fix test_asyncio on Cygwin

Skip tests on UNIX sockets since they hang on Cygwin.

Author: vstinner

Lib/test/support/socket_helper.py

@@ -149,6 +149,8 @@ def skip_unless_bind_unix_socket(test):
     """Decorator for tests requiring a functional bind() for unix sockets."""
     if not hasattr(socket, 'AF_UNIX'):
         return unittest.skip('No UNIX Sockets')(test)
+    if sys.platform == 'cygwin':
+        return unittest.skip('UNIX sockets hang on Cygwin')(test)
     global _bind_nix_socket_error
     if _bind_nix_socket_error is None:
         from .os_helper import TESTFN, unlink