bpo-31380: Skip test_httpservers test_undecodable_file on macOS. (#4720)

The undecodable file name cannot be created on macOS APFS file systems.
diff --git a/Lib/test/test_httpservers.py b/Lib/test/test_httpservers.py
index 20e6f66..cc829a5 100644
--- a/Lib/test/test_httpservers.py
+++ b/Lib/test/test_httpservers.py
@@ -384,7 +384,8 @@
         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,
diff --git a/Misc/NEWS.d/next/Tests/2017-12-04-23-19-16.bpo-31380.VlMmHW.rst b/Misc/NEWS.d/next/Tests/2017-12-04-23-19-16.bpo-31380.VlMmHW.rst
new file mode 100644
index 0000000..2baecf5
--- /dev/null
+++ b/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.