gh-133740: Fix locale.nl_langinfo(ALT_DIGITS) (#134468)

Set the LC_CTYPE locale to the LC_TIME locale even if
nl_langinfo(ALT_DIGITS) result is ASCII. The result is a list
separated by NUL characters and the code only checks the first list
item which can be ASCII whereas following items are non-ASCII.

Fix test__locale for the uk_UA locale on RHEL 7.

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