* Add support.MS_WINDOWS: True if Python is running on Microsoft Windows.
* Add support.MACOS: True if Python is running on Apple macOS.
* Replace support.is_android with support.ANDROID
* Replace support.is_jython with support.JYTHON
* Cleanup code to initialize unix_shell

Calling Py_Initialize() twice does nothing, instead of failing with a
fatal error: restore the Python 3.6 behaviour.

Increases coverage by 44%.

Add missing warning filter to test_exec_filename().

Increase the timeout from 1 min to 5 min.

Replace also time.time() with time.monotonic() for timeouts.

Every other menudef key is the lowercase version of the
corresponding main menu entry (in this case, 'Window').

Match Window on the main menu and remove last plural module name.
Change imports, test, and attribute references to match new name.

The revised file compiles, runs, and tests OK. idle_test/README.txt
explains how to use it to create new IDLE test files.

Initial What's New in Python 3.8 entry for `PYTHONPYCACHEPREFIX`.

Only make sure that the result is in unittest.signals._results, don't
check the full content of unittest.signals._results.

support._run_suite() uses TextTestRunner in verbose mode, but
TextTestRunner.run() calls registerResult(result) which made the test
fail with "odd object in result set".

Call also removeResult() to restore unittest.signals._results to
avoid test side effect.

Fix-up class name duplication in PR #7807. Combined effect is that
module calltips and its class CallTips are now calltip and Calltip.
In module calltip_w class CallTip is now CalltipWindow.

Signed-off-by: Srinivas Reddy Thatiparthy <thatiparthysreenivas@gmail.com>

Improve consistency and appearance. Module idlelib.calltips is now calltip.
Class idlelib.calltip_w.CallTip is now Calltip.

Part 3 of 3, continuing PR #7689. This covers 14 idlelib modules and their tests,
rpc to zoomheight except for run (already done) and tooltip (being done separately).

* Fix also PyInit__gdbm() to catch errors.
* test.pythoninfo: add gdbm.version
* test_dbm_gnu now logs GDBM_VERSION when run in verbose mode.

* pythoninfo: rename function to collect_gdbm()

Add -g to LDFLAGS when compiling with LTO to get debug symbols.

Fix test_dbm_gnu.test_reorganize() on macOS with gdbm 1.15: add a
larger value to make sure that the file size changes.

bpo-33671
* use memoryview() with size == file size on Windows, see https://github.com/python/cpython/pull/7160#discussion_r195405230
* release intermediate (sliced) memoryview immediately
* replace "OSX" occurrences with "macOS"
* add some unittests for copyfileobj()

with debuglevel=1 only the header keys got printed. With
this change the header values get printed as well and the single
header entries get '\n' as a separator.

Using gdbm 1.15, creating a database creates a file of 16 MiB. Adding
a small entry and then modifying the small entry doesn't change the
file size. Modify test_dbm_gnu to be less strict: allow that the file
size doesn't change.

This may help to investigate bpo-33901.

Part 2 of 3.  Continues PR #7689, changeset ee5ef309.
Edit and add tests for 18 modules, help_about to replace and run.

Make it the same as when one runs 'python'.

* Test exists(), lexists(), isdir(), isfile(), islink(), ismount()
  with bytes paths.
* Remove unneeded silencing DeprecationWarning for ismount() with
  bytes path.
* Test common functions with unencodable and undecodable paths.
* Minor clean up and refactoring.

In some development setups it is inconvenient or impossible to write bytecode
caches to the code tree, but the bytecode caches are still useful. The
PYTHONPYCACHEPREFIX environment variable allows specifying an alternate
location for cached bytecode files, within which a directory tree mirroring the code
tree will be created. This cache tree is then used (for both reading and writing)
instead of the local `__pycache__` subdirectory within each source directory.

Exposed at runtime as sys.pycache_prefix (defaulting to None), and can
be set from the CLI as "-X pycache_prefix=path".

Patch by Carl Meyer.

Mention that it can be triggered by triple quotes and after specifying decorators.

Update the the signature in the code example to make `_cache` a keyword-only parameter.

regrtest: Add warning when using less than 3 warmup runs like -R 1:3.