This reverts commit 2998a176.

Reason for revert: perf regressions crbug.com/835472

Original change's description:
> [heap] Removing marking step size ramp-up interval heuristic.
> 
> The heuristic is no longer needed now that we have concurrent marking.
> 
> Bug: chromium:834371
> Change-Id: I8ca3eaacdab618f690d8007aff66713260ace19f
> Reviewed-on: https://chromium-review.googlesource.com/1017123
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52693}

TBR=ulan@chromium.org,hpayer@chromium.org,mlippautz@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:834371
Change-Id: I574abd75e77ae9ff443419f01750a3f01072adaf
Reviewed-on: https://chromium-review.googlesource.com/1023890Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52728}