Gruen sumcheck optimization

[moodlezoup]

Implement the sumcheck optimization described in Section 3.2 of Angus Gruen's Some Improvements for the PIOP for ZeroCheck. Should apply to all of the sumchecks in Jolt.

Note that Jolt has already integrated the Dao-Thaler sumcheck optimization (for large EQ polynomial evaluations). That paper has a section describing how the two optimization interact.