Return the ISO 10646 comment of a code point as ICU 78.1 unames.cpp does
without character name data: it is the empty string for every code point.
A null or failed status returns 0 untouched, a negative capacity or a
null destination with a positive capacity sets U_ILLEGAL_ARGUMENT_ERROR,
and otherwise the destination is NUL-terminated with the usual
U_STRING_NOT_TERMINATED_WARNING when the capacity is zero.
The sceIcuUnknown stub with this NID is removed.
u_isISOControl returns true for U+0000..U+001F and U+007F..U+009F and
false for every other value including negative ones, as in ICU 78.1
uchar.cpp. u_forDigit maps a digit below the radix to a lowercase ASCII
digit or letter and returns 0 for a radix outside 2..36 or a digit that is
negative or not below the radix.
The two sceIcuUnknown stubs with these NIDs are removed.