restrict dispatch of some custrom string macros to `String` (#57781)
Restricts the dispatch for these macros so that only `String` (literal)
arguments are accepted:
* `int128_str`
* `uint128_str`
* `big_str`
* `ip_str` from the Sockets stdlib
* `dateformat_str` from the Dates stdlib
Some of these changes make the code in the sysimage less vulnerable to
invalidation.