Where possible, observable calls originating from within Temporal, that
require an options argument, should pass `undefined` as that options
argument, rather than `{}` or `Object.create(null)`.
See tc39/proposal-temporal#1685.
https://github.com/tc39/proposal-temporal/issues/1753 records the
consensus reached at the October 2021 TC39 meeting to disallow "-000000"
as an extended year, both in Date.parse and Temporal. This adds tests for
the Temporal part of that.