Look at recent split heap changes in MicroPython

[dhalbert]

This is of interest to us:
micropython#13219, merged instead of micropython#13035.

[tannewt]

The computation fix does look interesting but I don't think it is critical. I think the main question is if we want to spend the time on the merge now or after 9.0.

[dhalbert]

I also looked at this again and agree it didn't seem as crucial. I thinks this could wait until 9.later.

[tannewt]

I tried this with #8736 and didn't see much change. I agree that the computation is an improvement but don't think we need to track it separately. We'll get it automatically when we update MP next.