Issue #13441: Disable temporary the check on the maximum character until

the Solaris issue is solved.

But add assertion on the maximum character in various encoders: UTF-7, UTF-8,
wide character (wchar_t*, Py_UNICODE*), unicode-escape, raw-unicode-escape.

Fix also unicode_encode_ucs1() for backslashreplace error handler: Python is
now always "wide".