tests: Fix test to pass under latest asyncio/master

Author: 1st1

tests/test_tcp.py

@@ -242,7 +242,7 @@ async def client(addr):
             writer.write(b'AAAA')
             self.assertEqual(await reader.readexactly(2), b'OK')
 
-            re = r'(a bytes-like object is required)|(must be byte-ish)'
+            re = r'(a bytes-like object)|(must be byte-ish)'
             with self.assertRaisesRegex(TypeError, re):
                 writer.write('AAAA')