[3.6] bpo-31380: Skip test_httpservers test_undecodable_file on macOS. (GH-4720) (#4721)

The undecodable file name cannot be created on macOS APFS file systems.
(cherry picked from commit b3edde8)

Author: miss-islington

Lib/test/test_httpservers.py

@@ -370,7 +370,8 @@ def close_conn():
         reader.close()
         return body
 
-    @support.requires_mac_ver(10, 5)
+    @unittest.skipIf(sys.platform == 'darwin',
+                     'undecodable name cannot always be decoded on macOS')
     @unittest.skipIf(sys.platform == 'win32',
                      'undecodable name cannot be decoded on win32')
     @unittest.skipUnless(support.TESTFN_UNDECODABLE,

Misc/NEWS.d/next/Tests/2017-12-04-23-19-16.bpo-31380.VlMmHW.rst

@@ -0,0 +1 @@
+Skip test_httpservers test_undecodable_file on macOS: fails on APFS.