This has been broken ever since we added multiple timeline-tracks.

Drive-by-fix: Rename selectionMouseMove to selectTimeRange.

Bug: v8:10644
Change-Id: Icff06a2d636a4a7302ac406f99e1012be4c7f25f
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2463240
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran  <gsathya@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70443}