[TabStripDedupe] Implement declutter method for dedupe.

This CL removes tabs tied to a url that needs to be decluttered keeping the oldest tab. It uses the last committed time for the oldest tab computation and if that is not present in certain edge cases deprioritizes the tab versus other duplicate tabs to keep.

Change-Id: I3ff156786da3907cc02e3cf6ea09d87723816bef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6086305
Reviewed-by: Emily Shack <emshack@chromium.org>
Commit-Queue: Shibalik Mohapatra <shibalik@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1394990}