Revert of [counters] RuntimeStats: fix wrong bookkeeping when dynamically changing counters. (patchset #10 id:180001 of https://codereview.chromium.org/2511093002/ )

Reason for revert:
Wronged it even more.

Original issue's description:
> [counters] RuntimeStats: fix wrong bookkeeping when dynamically changing counters
>
> RuntimeTimerScopes always subtract their own time from the parent timer's
> counter to properly account for the own time. Once a scope is destructed it
> adds it own timer to the current active counter. However, if the current
> counter is changed with CorrectCurrentCounterId we will attribute all the
> subtimers to the previous counter, and add the own time to the new counter.
> This way it is possible to end up with negative times in certain counters but
> the overall would still be correct.
>
> BUG=
>
> Committed: https://crrev.com/f6c74d964d9387df4bed3d8c1ded51eb9e8aa6e8
> Cr-Commit-Position: refs/heads/master@{#41142}

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

Review-Url: https://codereview.chromium.org/2519073002
Cr-Commit-Position: refs/heads/master@{#41150}