Issue 11875: Keep OrderedDict's __reduce__ from temporarily mutating the object.

diff --cc Lib/collections/__init__.py
Simple merge

diff --cc Misc/NEWS
index 62eb3ab2d1a6a1bffd1fb78d9c1677037bc4e4bc,1885fb73cf9bb1258b89c870804467d942a93f24..27be0ccdf4b78fc373325611b428371bb734fced
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -110,17 -60,11 +110,20 @@@ Core and Builtin
  Library
  -------
  
 +- Issue #11731: simplify/enhance email parser/generator API by introducing
 +  policy objects.
 +
 +- Issue #11768: The signal handler of the signal module only calls
 +  Py_AddPendingCall() for the first signal to fix a deadlock on reentrant or
 +  parallel calls. PyErr_SetInterrupt() writes also into the wake up file.
 +
 +- Issue #11492: fix several issues with header folding in the email package.
 +
  - Issue #11852: Add missing imports and update tests.
  
+ - Issue #11875: collections.OrderedDict's __reduce__ was temporarily
+   mutating the object instead of just working on a copy.
+ 
  - Issue #11467: Fix urlparse behavior when handling urls which contains scheme
    specific part only digits. Patch by Santoso Wijaya.