Now, when we click an instruction in the register allocation phase we
will have highlighted both the middle panel and right panel.
Previously only the right panel was highlighted.

Note that the reverse is not yet true (i.e. clickin the right panel
does not highlight the middle panel).

Bug: v8:7327
Notry: true
Change-Id: Ia45d54a33587eac3706d5fbf56e01f19d6f94144
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3001170
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75575}