Python 2.7 doesn't have FileNotFoundError exception: use OSError and
errno.ENOENT.

"python -m test --huntrleaks ..." now also checks for leak of file
descriptors.
Co-Authored-By: Richard Oudkerk <shibturn@gmail.com>

* test_tempfile.test_no_leak_fd() mocks os.close() but it doesn't
  call the original os.close() method and so leaks an open file
  descriptor. Fix the test by calling the original os.close()
  function.
* test_posix.test_fdopen_directory(): close the directory file
  descriptor when the test completes.

* Add support.wait_threads_exit(): context manager looping at exit
  until the number of threads decreases to its original number.
* Add some missing thread.join()
* test_asyncore.test_send(): call explicitly t.join() because the cleanup
  function is only called outside the test method, whereas the method
  has a @test_support.reap_threads decorator
* test_hashlib: replace threading.Event with thread.join()
* test_thread:

  * Use wait_threads_exit() context manager
  * Replace test_support with support
  * test_forkinthread(): check child process exit status in the
    main thread to better handle error.

Hide "recursedown('@test_9296_tmp')" message.

Backport manually regrtest enhancements from master:

* No longer clear filters, like --match, to re-run failed tests in
  verbose mode (-w option).
* Tests result: always indicate if tests have been interrupted.
* Enhance tests summary
* After failing tests are re-run, display again the summary.
* Add environment_altered to test.support, but it's currently unused
* regrtest: count also ENV_CHANGED as failures
* regrtest: Enhance format_duration()
* Replace test_support with support

(cherry picked from commit f7745e1d)
Co-authored-by: Tobias Kunze <r@rixx.de>

The bytes parameter uses big endian.
(cherry picked from commit b75ec085)
Co-authored-by: Farhaan Bukhsh <farhaan.bukhsh@gmail.com>

* Prevent spurious message if taking a shortcut
* Fix YAML style
* Disable largefile tests

It depended on a global variable set by other tests..
(cherry picked from commit 7cfd8c6a)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit e36837cb)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

(cherry picked from commit e905c844)

Separate tests leaked files or were depended on files leaked in other tests.
(cherry picked from commit 027f95c7)

`writerows()` takes an iterable.
(cherry picked from commit a801cf16)
Co-authored-by: Zackery Spytz <zspytz@gmail.com>

Use also support.SOCK_MAX_SIZE, not only support.PIPE_MAX_SIZE, to
get the size for a blocking send into a multiprocessing pipe.

Replace also test_support with support.

* bpo-31479: Always reset the signal alarm in tests

Use "try: ... finally: signal.signal(0)" pattern to make sure that
tests don't "leak" a pending fatal signal alarm.

* Move two more alarm() calls into the try block

Fix also typo: replace signal.signal(0) with signal.alarm(0)

* Move another signal.alarm() into the try block

(cherry picked from commit 9abee722)

* bpo-33717: pythoninfo: add CC --version (GH-7290)

Python 3.6, although I've seen the same crash in 3.6 (when involving
extension types and more complicated threading setups).

(cherry picked from commit a5c42284)

Fix test_multiprocessing.test_ignore(): use support.PIPE_MAX_SIZE
to make sure that send_bytes() blocks.

It is reproduced when parse the "<>" operator and run
Python with both options -3 and -We.

Check which readline implementation is used based on the readline
docstring.

Rename Lib/test/bisect.py to Lib/test/bisect_cmd.py. The old name was
in conflict with Lib/bisect.py, causing test failures, depending how
tests were run.

For example, "python2.7 Lib/test/test_httpservers.py" imported
indirectly Lib/test/bisect.py instead of Lib/bisect.py
on "import bisect".

* Add a space to ensurepip's --altinstall option
* Add periods to the arguments of ensurepip that didn't have it

This makes --help for all optional arguments consistent and also makes it
consistent with pip --help..
(cherry picked from commit e9537ad6)
Co-authored-by: Wieland Hoffmann <mineo@users.noreply.github.com>

(cherry picked from commit 8c1ad0c4)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

Call sys.stdout.flush() after displaying "running: ...".

(cherry picked from commit 268cc7c3)

Co-authored-by: Andrés Delfino adelfino@gmail.com

Skip test_load_dh_params() of test_ssl when Python filesystem encoding
cannot encode the provided path.

* Fixed a leak when the GC fails to add an object with __del__ into
  the gc.garbage list.
* PyGC_Collect() can now be called when an exception is set and
  preserves it.
(cherry picked from commit 301e3cc8)

(cherry picked from commit d5f14426)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

(cherry picked from commit 1179f4b4)
Co-authored-by: INADA Naoki <methane@users.noreply.github.com>

uuid._ipconfig_getnode did not validate the maximum length of the value,
so long as the value had the same type of formatting as a MAC address.
This let it select DUIDs as MAC addresses. It now requires an exact
length match..
(cherry picked from commit c66c342c)
Co-authored-by: CtrlZvi <viz+github@flippedperspective.com>

Fixes incorrect error text for int('1', base=1000)
and long('1', base=1000).

(cherry picked from commit bde3e0bf)

(cherry picked from commit 19177fbd)
Co-authored-by: Stéphane Wirtel <stephane@wirtel.be>

The robotparser's __str__ representation now includes wildcard
entries.
(cherry picked from commit c3fa1f2b93fa4bf96a8aadc74ee196384cefa31e)

Co-authored-by: Michael Lazar <lazar.michael22@gmail.com>.

Clarify that flush is implied when the call to write contains a newline character.
(cherry picked from commit 7ffd4c58)
Co-authored-by: Elena Oat <oat.elena@gmail.com>

(cherry picked from commit ddb6215a)