Merge: #22233: Only split headers on \r and/or \n, per email RFCs.

diff --cc Lib/test/test_email/test_email.py
Simple merge

diff --cc Lib/test/test_httplib.py
Simple merge

diff --cc Misc/NEWS
index 56d8434d810c6d032a4cf8128f507af5d7b73d23,9437b86f30de8177b2831277586f87d9c3fb9abd..71598b7c473e05bacab801b8d4860dfe225b8c07
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -91,21 -41,33 +91,25 @@@ Core and Builtin
  Library
  -------
  
+ - Issue #22233: Break email header lines *only* on the RFC specified CR and LF
+   characters, not on arbitrary unicode line breaks.  This also fixes a bug in
+   HTTP header parsing.
+ 
 +- Issue 27331: The email.mime classes now all accept an optional policy keyword.
 +
  - Issue 27988: Fix email iter_attachments incorrect mutation of payload list.
  
 +- Issue #16113: Add SHA-3 and SHAKE support to hashlib module.
 +
 +- Eliminate a tautological-pointer-compare warning in _scproxy.c.
 +
 +- Issue #27776: The :func:`os.urandom` function does now block on Linux 3.17
 +  and newer until the system urandom entropy pool is initialized to increase
 +  the security. This change is part of the :pep:`524`.
 +
 +- Issue #27778: Expose the Linux ``getrandom()`` syscall as a new
 +  :func:`os.getrandom` function. This change is part of the :pep:`524`.
 +
  - Issue #27691: Fix ssl module's parsing of GEN_RID subject alternative name
    fields in X.509 certs.