pythongh-133767: Fix use-after-free in the unicode-escape decoder with an error handler (pythonGH-129648) (pythonGH-133944)

If the error handler is used, a new bytes object is created to set as
the object attribute of UnicodeDecodeError, and that bytes object then
replaces the original data. A pointer to the decoded data will became invalid
after destroying that temporary bytes object. So we need other way to return
the first invalid escape from _PyUnicode_DecodeUnicodeEscapeInternal().

_PyBytes_DecodeEscape() does not have such issue, because it does not
use the error handlers registry, but it should be changed for compatibility
with _PyUnicode_DecodeUnicodeEscapeInternal().
(cherry picked from commit 9f69a58)
(cherry picked from commit 6279eb8)
(cherry picked from commit a75953b)
(cherry picked from commit 0c33e5b)

Co-authored-by: Serhiy Storchaka <[email protected]>
Part-of: python#134345
Closes: python#134345
Signed-off-by: Michał Górny <[email protected]>

Author: serhiy-storchaka

Lib/test/test_codeccallbacks.py

@@ -1,6 +1,7 @@
 import codecs
 import html.entities
 import itertools
+import re
 import sys
 import unicodedata
 import unittest