Need test for Intl NumberFormat v3 API

[FrankYFTang]

Intl NumberFormat v3 API advanced to Stage 3 in TC39 2021 July meeting. We need tests for it. https://github.com/tc39/proposal-intl-numberformat-v3 @sffc

[jugglinmike]

I'll give it a shot!

[jugglinmike]

I'm currently writing tests for signDisplay: "negative"

[jugglinmike]

Here's a progress update:

feature	status
formatRange	under review
Grouping Enum	under review
New Rounding/Precision Options	under review
Interpret Strings as Decimals	under review
Rounding Modes	complete
Sign Display Negative	complete

[jugglinmike]

I'll take "Interpret Strings as Decimals", next

[jugglinmike]

I'll take "New Rounding/Precision Options", now