Add STIX Two Math?

[**STIX Two project**](https://github.com/stipub/stixfonts)

Now that Noto Sans Math is live on Google Fonts, is it time to revisit including the STIX Two Math font? As I recall, this was briefly available but then removed because of lack of support for math fonts.

This is an exploratory question at this time rather than a formal add request. The current release version of the STIX Two Math font is one development cycle behind the most recent development work, and additional work items are planned—but not scheduled—before the next release.