ignored by the buffered IO layer anymore.

fix issue #9129: added proper error handling when accepting new connections in SMTPServer.handle_accept

Write test.support.workaroundIssue8611() function so it will be easier to
remove this workaround from all tests.

The test is still failing on "x86 FreeBSD 7.2 3.x" and "sparc solaris10 gcc
3.x" buildbots. It looks like the locale encoding is able to decode b'\xff'. I
suppose that it is an encoding like 'iso-8859-1'.

Use C locale to set, I hope, the locale encoding to 'ascii'. Display also the
encoding so if the test fails, at least I will learn the locale encoding
choosen for the C locale.

There are buildbot failures on "x86 FreeBSD 3.x" and "sparc solaris10 gcc 3.x".
I suppose that _Py_char2wchar() doesn't fail even if the locale encoding is
unable to decode the byte string, because _Py_char2wchar() has a special mode
for platform without mbrtowc() (ISO C99) function.

Let's check my theory by avoid error on the Python print() instruction.

Also remove one tab, and move a check closer to the possible failure.

Failure to do it may result in strange error messages or even crashes,
in admittedly convoluted cases that are normally syntax errors, like:
    def f(*xx, __debug__): pass

Catch BytesWarning exceptions.

 * Check fs encoding value on Windows
 * Ignore LANG= test on Windows and Mac OS X (fs encoding is hardcoded on these
   platforms)

error handler, or strict error handler on Windows.

 * Rewrite os.fsencode() documentation
 * Improve os.fsencode and os.fsdecode() tests using the new PYTHONFSENCODING
   environment variable