Check if data is decoded by os.fsdecode() (filesystem encoding with
surrogateescape error handler, PEP 383), not by UTF-8 or the filesystem
encoding in strict mode.

Use TESTFN_UNDECODABLE in test_cmd_line_script.test_non_ascii() on UNIX.

#13301: use ast.literal_eval() instead of eval() in Tools/i18n/msgfmt.py.  Patch by Serhiy Storchaka.

Thanks to Yongzhi Pan.

Thanks to Yongzhi Pan.

Thanks to Yongzhi Pan.

Thanks to Yongzhi Pan from docs@

Thanks to Yongzhi Pan from docs@

Thanks to Yongzhi Pan from docs@

from a Decimal argument.

Patch by Victor Stinner.

Patch by Victor Stinner.

Patch by Victor Stinner.

 * Remove unicode_widen(): replaced with _PyUnicodeWriter_Prepare()
 * Remove unicode_putchar(): replaced with
   PyUnicodeWriter_Prepare() + PyUnicode_WRITER()
 * When handling an decoding error, only overallocate the buffer by +25%
   instead of +100%