Drive-by-fix:
- Remove duplicated LazyTable
- Introduce more pseudo private _* fields
- Remove MapPanel.mapDetails getter
- Rename MapDetails.setSelectedMap to .map

Bug: v8:10644
Change-Id: I0f976ab86f24de2677e024e386e7d4169c9abbb3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2523192
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71093}