#11554: reactivate test_email_codecs, and make it pass.

The fix is to charset.py, which was not doing the encoding to the
correct output character set when doing a body_encode for either
the shift-jis or euc-jp charsets.  There's also a fix for handling
a bytes input in encoders.py.

Patch by Michael Henry, comment changes by me.
diff --git a/Misc/ACKS b/Misc/ACKS
index a1197ad..8938267 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -371,6 +371,7 @@
 Jason Hildebrand
 Richie Hindle
 Konrad Hinsen
+Michael Henry
 David Hobley
 Tim Hochberg
 Joerg-Cyril Hoehle