Fix performance bottlenecks when multi buffers have huge numbers of buffers (#26308)

This is motivated by trying to make the Project Diff view usable with
huge Git change sets.

Release Notes:

- Improved performance of rendering multibuffers with very large numbers
of buffers
4846e6fb3aMax Brunsfeld committed on 3/8/2025, 2:15:15 AM· committed by GitHubparentcb543f9
3 files changedLine totals unavailable