Case-sensitivity discrepancy between "new Temporal.TimeZone" and "Temporal.TimeZone.from"

[ptomato]

From #2292:

Temporal.TimeZone.from("pst8pdt") is still not accepted even though new Temporal.TimeZone("pst8pdt") works, but that's consistent with how new Temporal.TimeZone("etc/gmt+1") is treated differently than Temporal.TimeZone.from("etc/gmt+1").

This is surprising to me, I'd expect them to have the same case-sensitivity, but if there were any difference I'd expect from() to be more lenient.

Check if this is the case with calendars as well.

cc @anba @gibson042

[gibson042]

IsValidTimeZoneName is explicitly ASCII-case-insensitive and used by both Temporal.TimeZone and Temporal.TimeZone.from (the latter via ToTemporalTimeZone). I would expect uniformity.

[ptomato]

This is mostly taken care of by CanonicalizeTimeZoneName, the only change is that we have to make IANA legacy names like "PST8PDT" valid case-insensitively, so that e.g. 2022-08-30T14:27[pst8pdt] is accepted.

For calendars we currently don't accept anything but lowercase, but that seems out of line with what ECMA-402 currently does. e.g. both of these are fine:

new Date().toLocaleString('en', {calendar: 'heBREw'})
new Date().toLocaleString('en-u-ca-heBREw')

So, I'd propose to accept calendar names case-insensitively as well.

To summarize, all of the following should work:

new Temporal.TimeZone('eTc/gMt+1')
Temporal.TimeZone.from('eTc/gMt+1')
Temporal.TimeZone.from('2022-08-30T14:29[eTc/gMt+1]')
new Temporal.Calendar('jApAnEsE')
Temporal.Calendar.from('jApAnEsE')
Temporal.Calendar.from('2022-08-30[u-ca=jApAnEsE]')