Also add AOs: AddDurationToOrSubtractDurationFromPlainYearMonth,
CreateNegatedDurationRecord

Spec Text:
https://tc39.es/proposal-temporal/#sec-temporal.plainyearmonth.prototype.add
https://tc39.es/proposal-temporal/#sec-temporal.plainyearmonth.prototype.subtract
https://tc39.es/proposal-temporal/#sec-temporal-adddurationtoorsubtractdurationfromplainyearmonth

Also see https://github.com/tc39/proposal-temporal/pull/2281

Bug: v8:11544
Change-Id: I5ca6acc82dad07a8dd202de02bca5a16e585e84c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3697180
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81228}