- Introduce LazyTable that only shows the first 100 entries and can
  lazily expand
- Make StatsPanel.update method async to not block the UI
- Show "Total" entry as last item in StatsPanel tables
- Fix StatsPanel table entries text alignment
- Remove unused getters from StatsPanel class

Drive-by-fix:
- MapPanel._displayedMapsInTree is undefined when expanding to
  a sub-transition tree

Bug: v8:10644
Change-Id: I5ce7c8b1ee825515cf790a3e52534c3069d8be89
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2507716
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70903}