libstdc++: Support old and new T_FMT for en_HK locale [PR103687]

This checks whether the locale data for en_HK includes %p and adjusts
the string being tested accordingly. To account for Jakub's fix to make
%I parse "12" as 0 instead of 12, we need to change the expected value
for the case where the locale format doesn't include %p. Also change the
time from 12:00:00 to 12:02:01 so we can tell if the minutes and seconds
get mixed up.

libstdc++-v3/ChangeLog:

	PR libstdc++/103687
	* testsuite/22_locale/time_get/get_date/wchar_t/4.cc: Restore
	original locale before returning.
	* testsuite/22_locale/time_get/get_time/char/2.cc: Check for %p
	in locale's T_FMT and adjust accordingly.
	* testsuite/22_locale/time_get/get_time/wchar_t/2.cc: Likewise.