Make Timeline.selectTimeRange run in O(log(n)) instead of
O(n) comparisons.

Drive-by-fix:
- Use *Index for variable names in Timeline

Bug: v8:10644
Change-Id: I65f3be9f259e6bebcec489526a54712daffd4d15
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2507714
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Auto-Submit: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71461}