[3.14] gh-53203: Fix strptime() for %c, %x and %X formats on some locales (GH-135971) (GH-136019)

* Add detection of decimal non-ASCII alt digits.
* Add support of non-decimal alt digits on locale lzh_TW.
* Accept only numbers in correct range if alt digits are known.
* Fix bug in detecting the position of the week day name on locales byn_ER and wal_ET.
* Fix support of single-digit hour on locales ar_SA and bg_BG.
* Add support for %T, %R, %r, %C, %OC.
* Prepare code to use nl_langinfo().

(cherry picked from commit 07183ebce36462aaaea4d20e0502b20821dd2682)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>