Merge 3.5.

diff --cc Misc/NEWS
index 0ce19569372a96b54a75f9fbd2ebe053e7885977,723342ced13ac726df3f78764b7cec77d4974a19..87fa371705bd41b685bf7233a9d2acf0d666704c
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -294,13 -132,6 +294,11 @@@ Librar
  - Issue #26873: xmlrpc now raises ResponseError on unsupported type tags
    instead of silently return incorrect result.
  
- - Issue #26881: modulefinder now works with bytecode with extended args.
- 
 +- Issue #26915:  The __contains__ methods in the collections ABCs now check
 +  for identity before checking equality.  This better matches the behavior
 +  of the concrete classes, allows sensible handling of NaNs, and makes it
 +  easier to reason about container invariants.
 +
  - Issue #26711: Fixed the comparison of plistlib.Data with other types.
  
  - Issue #24114: Fix an uninitialized variable in `ctypes.util`.