Also add the non-intl version of AO
GetIANATimeZoneOffsetNanoseconds which only implement for UTC.
(intl version implement other tz come later)

Also fix bug in JSTemporalTimeZone::offset_nanoseconds() that
"1000000L * offset_milliseconds()" may overflow int32_t before returning as int64_t by first casting offset_milliseconds() to int64_t in the operation so the whole formula is calculating under 64 bits not 32 bits. This bug fix some  *timezone-string-datetime tests.

Spec Text:
https://tc39.es/proposal-temporal/#sec-temporal.timezone.prototype.getoffsetnanosecondsfor
https://tc39.es/proposal-temporal/#sec-temporal.timezone.prototype.getoffsetstringfor
https://tc39.es/proposal-temporal/#sec-temporal-getianatimezoneoffsetnanoseconds

Bug: v8:11544
Change-Id: I2227dbfc8d6ed3ef83edcef5a9b903b8642b5902
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3534622Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80606}