More email package related repairs. This fixes smtplib's import and use of

email.base64mime, but test_smtplib still has failures for me.  They are
timeout errors so think they're more related to my current wacky network setup
than bugs remaining in the code related to the email package.

This also r57693 that got clobbered with the sandbox sync, and fixes a couple
of other minor problems that cropped up.  I will kill the sandbox branch next.

The email package now has 11F/11E.

Lib/email/message.py

@@ -201,7 +201,8 @@ class Message:
                 # Incorrect padding
                 pass
         elif cte in ('x-uuencode', 'uuencode', 'uue', 'x-uue'):
-            in_file = BytesIO(bytes(payload + '\n'))
+            payload += '\n'
+            in_file = BytesIO(payload.encode('raw-unicode-escape'))
             out_file = BytesIO()
             try:
                 uu.decode(in_file, out_file, quiet=True)
@@ -752,7 +753,8 @@ class Message:
                 # LookupError will be raised if the charset isn't known to
                 # Python.  UnicodeError will be raised if the encoded text
                 # contains a character not in the charset.
-                charset = str(bytes(charset[2]), pcharset)
+                as_bytes = charset[2].encode('raw-unicode-escape')
+                charset = str(as_bytes, pcharset)
             except (LookupError, UnicodeError):
                 charset = charset[2]
         # charset characters must be in us-ascii range