Normalize the encoding names for Latin-1 and UTF-8 to
'latin-1' and 'utf-8'.

These are optimized in the Python Unicode implementation
to result in more direct processing, bypassing the codec
registry.

Also see issue11303.
diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index 9ad9eed..d97894c 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -1182,11 +1182,14 @@
         self.assertEqual('hello'.encode('ascii'), b'hello')
         self.assertEqual('hello'.encode('utf-7'), b'hello')
         self.assertEqual('hello'.encode('utf-8'), b'hello')
-        self.assertEqual('hello'.encode('utf8'), b'hello')
+        self.assertEqual('hello'.encode('utf-8'), b'hello')
         self.assertEqual('hello'.encode('utf-16-le'), b'h\000e\000l\000l\000o\000')
         self.assertEqual('hello'.encode('utf-16-be'), b'\000h\000e\000l\000l\000o')
         self.assertEqual('hello'.encode('latin-1'), b'hello')
 
+        # Default encoding is utf-8
+        self.assertEqual('\u2603'.encode(), b'\xe2\x98\x83')
+
         # Roundtrip safety for BMP (just the first 1024 chars)
         for c in range(1024):
             u = chr(c)