This is a normative change in the ECMA-402 spec. See:
https://github.com/tc39/ecma402/commit/7508197
In our implementation, we don't have the affected AOs directly, as we
delegate to ICU. So instead, we must ensure we provide ICU a locale with
the relevant extension keys present.
In ICU 76, the default was changed from "arab" to "latn". See:
c149724509
The whole point of these tests was to use a non-Latin numbering system.
This patch ensures that is the case to make following patches easier to
grok.
