Refactor to reduce code duplication in `Tools/scripts/summarize_stats.py`

[mdboom]

Feature or enhancement

Proposal:

The summarize_stats.py script operates in two modes: single and comparison. It grew these two modes somewhat organically, and there is a lot of code duplication and opportunity for these two modes to diverge. By refactoring to have each of the tables know how to present themselves in both modes, we should reduce the overall amount of code and these kinds of bugs. This refactor should be helpful in advance of the many new stats we plan to add for the Tier 2 interpreter.

Cc: @brandtbucher, @markshannon

Has this already been discussed elsewhere?

No response given

Links to previous discussion of this feature:

Related: #109329

Linked PRs

• gh-110019: Refactor summarize_stats #110398

[hugovk]

Thanks!