asyncio: Support host=b'' for getaddrinfo

Lib/asyncio/base_events.py

@@ -102,7 +102,7 @@ def _ipaddr_info(host, port, family, type, proto):
     else:
         return None
 
-    if port in {None, ''}:
+    if port in {None, '', b''}:
         port = 0
     elif isinstance(port, (bytes, str)):
         port = int(port)

Lib/test/test_asyncio/test_base_events.py

@@ -130,6 +130,10 @@ class BaseEventTests(test_utils.TestCase):
             (INET, STREAM, TCP, '', ('1.2.3.4', 0)),
             base_events._ipaddr_info('1.2.3.4', None, INET, STREAM, TCP))
 
+        self.assertEqual(
+            (INET, STREAM, TCP, '', ('1.2.3.4', 0)),
+            base_events._ipaddr_info('1.2.3.4', b'', INET, STREAM, TCP))
+
         self.assertEqual(
             (INET, STREAM, TCP, '', ('1.2.3.4', 0)),
             base_events._ipaddr_info('1.2.3.4', '', INET, STREAM, TCP))