Issue #20753: Skip PasswordProtectedSiteTestCase when Python is built without threads.
Issue #20753: Merge with 3.4.
Fixes #10541: regrtest -T is broken

 * makes test_trace tests restore the tracefunc after they run
 * write_results() in trace module will not terminate if lnotab
   cannot be found.
Issue #21778:  Clarify use of flags if PyBuffer_FillInfo() is used inside a
getbufferproc().
Merge 3.4.
Issue #21679: Prevent extraneous fstat() calls during open().  Patch by Bohuslav Kabrda.
Issue #14235: Use importlib.reload() in test_cmd.test_coverage.
Issue #14235: Merge from 3.4.
Issue #21811: Add Misc/NEWS entry.
Issue #21811: Add Misc/NEWS entry.
Fix typo in socket.getaddrinfo() docstring.

Reported by Krishna Kumar Thakur on docs@.
Fix typo in socket.getaddrinfo() docstring.

Reported by Krishna Kumar Thakur on docs@.
Issue #21645: asyncio: add a watchdog in test_read_all_from_pipe_reader() for
debug
asyncio: sync with Tulip

- Sort imports
- Simplify/optimize iscoroutine(). Inline inspect.isgenerator(obj): replace it
  with isinstance(obj, types.GeneratorType)
- CoroWrapper: check at runtime if Python has the yield-from bug #21209.  If
  Python has the bug, check if CoroWrapper.send() was called by yield-from to
  decide if parameters must be unpacked or not.
- Fix "Task was destroyed but it is pending!" warning in
  test_task_source_traceback()
asyncio: sync with Tulip

- Sort imports
- Simplify/optimize iscoroutine(). Inline inspect.isgenerator(obj): replace it
  with isinstance(obj, types.GeneratorType)
- CoroWrapper: check at runtime if Python has the yield-from bug #21209.  If
  Python has the bug, check if CoroWrapper.send() was called by yield-from to
  decide if parameters must be unpacked or not.
- Fix "Task was destroyed but it is pending!" warning in
  test_task_source_traceback()
Issue #21163: BaseEventLoop.run_until_complete() and test_utils.run_briefly()
don't log the "destroy pending task" message anymore. The log is redundant for
run_until_complete() and useless in run_briefly().
(Merge 3.4) Issue #21163: BaseEventLoop.run_until_complete() and
test_utils.run_briefly() don't log the "destroy pending task" message anymore.
The log is redundant for run_until_complete() and useless in run_briefly().
Issue #21882: In turtle demos, remove module scope gui and sys calls by
either deleting or moving to the module's main function.
Merge with 3.4
Issue #18592: Add unittests for SearchDialogBase. Patch by Phil Webster.