Revert "[3.8] bpo-27657: Fix urlparse() with numeric paths (GH-16839)" (GH-18525)

This reverts commit 0f3187c1ce3b3ace60f6c1691dfa3d4e744f0384.

The change broke the backwards compatibility of parsing behavior in a
patch release of Python (3.8.1). A decision was taken to revert this
patch in 3.8.2.

In https://bugs.python.org/issue27657 it was decided that the previous
behavior like

>>> urlparse('localhost:8080')
ParseResult(scheme='', netloc='', path='localhost:8080', params='', query='', fragment='')

>>> urlparse('undefined:8080')
ParseResult(scheme='', netloc='', path='undefined:8080', params='', query='', fragment='')

needs to be preserved in patch releases as number of users rely upon it.

Explicitly mention the releases involved with the revert in NEWS.
Adopt the wording suggested by @ned-deily.
diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py
index 7625007..4ae6ed3 100644
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -709,17 +709,15 @@
 
     def test_portseparator(self):
         # Issue 754016 makes changes for port separator ':' from scheme separator
-        self.assertEqual(urllib.parse.urlparse("http:80"), ('http','','80','','',''))
-        self.assertEqual(urllib.parse.urlparse("https:80"), ('https','','80','','',''))
-        self.assertEqual(urllib.parse.urlparse("path:80"), ('path','','80','','',''))
+        self.assertEqual(urllib.parse.urlparse("path:80"),
+                ('','','path:80','','',''))
         self.assertEqual(urllib.parse.urlparse("http:"),('http','','','','',''))
         self.assertEqual(urllib.parse.urlparse("https:"),('https','','','','',''))
         self.assertEqual(urllib.parse.urlparse("http://www.python.org:80"),
                 ('http','www.python.org:80','','','',''))
         # As usual, need to check bytes input as well
-        self.assertEqual(urllib.parse.urlparse(b"http:80"), (b'http',b'',b'80',b'',b'',b''))
-        self.assertEqual(urllib.parse.urlparse(b"https:80"), (b'https',b'',b'80',b'',b'',b''))
-        self.assertEqual(urllib.parse.urlparse(b"path:80"), (b'path',b'',b'80',b'',b'',b''))
+        self.assertEqual(urllib.parse.urlparse(b"path:80"),
+                (b'',b'',b'path:80',b'',b'',b''))
         self.assertEqual(urllib.parse.urlparse(b"http:"),(b'http',b'',b'',b'',b'',b''))
         self.assertEqual(urllib.parse.urlparse(b"https:"),(b'https',b'',b'',b'',b'',b''))
         self.assertEqual(urllib.parse.urlparse(b"http://www.python.org:80"),