Revert of [heap] Simplify heuristics for incremental step size. (patchset #5 id:180001 of https://codereview.chromium.org/2290333002/ )

Reason for revert:
Regressed GC times in v8.infinite_scroll_tbmv2 benchmarks.

Original issue's description:
> [heap] Simplify heuristics for incremental step size.
>
> This patch removes the code for speeding up marking.
>
> Now the step size depends on allocated bytes and
> invoked write barriers.
>
> We also ensure that the step size is large enough to
> justify the overhead of interrupting the generated code.
>
> BUG=chromium:616434
> LOG=NO
>
> Committed: https://crrev.com/71a793e4b1026e69d4009df0a419fe260fe1a235
> Cr-Commit-Position: refs/heads/master@{#39067}

TBR=mlippautz@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:616434

Review-Url: https://codereview.chromium.org/2304613002
Cr-Commit-Position: refs/heads/master@{#39098}