Revert of [ObjC ARC] Converts ios/chrome/browser/ui/bookmarks:bookmarks_arc_2 to ARC. (patchset #4 id:60001 of https://codereview.chromium.org/2737603007/ )

Reason for revert:
EG bookmarks tests started failing after this CL. Here is the first failure:
https://build.chromium.org/p/chromium.fyi/builders/EarlGreyiOS/builds/25193

Original issue's description:
> [ObjC ARC] Converts ios/chrome/browser/ui/bookmarks:bookmarks_arc_2 to ARC.
>
> Automatically generated ARCMigrate commit
> Notable issues:None
> BUG=624363
> TEST=None
>
> Review-Url: https://codereview.chromium.org/2737603007
> Cr-Commit-Position: refs/heads/master@{#456064}
> Committed: https://chromium.googlesource.com/chromium/src/+/dfc151cf408ffc92bfdc1d40f06487f8a256bc0a

TBR=lpromero@chromium.org,stkhapugin@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=624363

Review-Url: https://codereview.chromium.org/2738053008
Cr-Commit-Position: refs/heads/master@{#456084}
18 files changed