bpo-37531: Skip test_regrtest.test_multiprocessing_timeout() on all platforms (GH-16282)

diff --git a/Lib/test/test_regrtest.py b/Lib/test/test_regrtest.py
index 5091199..fa37ecd 100644
--- a/Lib/test/test_regrtest.py
+++ b/Lib/test/test_regrtest.py
@@ -1151,8 +1151,7 @@
                                   env_changed=[testname],
                                   fail_env_changed=True)
 
-    @unittest.skipIf(sys.platform == 'win32',
-                     'bpo-37531, bpo-38207: test hangs randomly on Windows')
+    @unittest.skipIf(True, 'bpo-37531, bpo-38207: test hangs randomly')
     def test_multiprocessing_timeout(self):
         code = textwrap.dedent(r"""
             import time