- Add CollapsableElement helper
- Collapse all panels by default
- Only update panels if they are opened
- Only update CodePanel Select element if the data has changed
- Fix focusing SourcePosition selection

Bug: v8:10644
Change-Id: Id9b5159e86623c7ca0f437dd9db6b0faff3ec573
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2859952
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Patrick Thier <pthier@chromium.org>
Commit-Queue: Patrick Thier <pthier@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74329}