Revert of "[heap] Divide available memory upon compaction tasks" (patchset #2 id:20001 of https://codereview.chromium.org/1399403002/ )

Reason for revert:
Failing: https://chromegw.corp.google.com/i/client.v8/builders/V8%20Linux64%20GC%20Stress%20-%20custom%20snapshot/builds/2115

Original issue's description:
> Reland of "[heap] Divide available memory upon compaction tasks"
>
> This reverts commit ec1046f9.
>
> Original message:
>
> [heap] Divide available memory upon compaction tasks
> - Fairly (round-robin) divide available memory upon compaction tasks.
> - Ensure an upper limit (of memory) since dividing is O(n) for n free-space
>   nodes.
> - Refill from free lists managed by sweeper once a compaction space becomes
>   empty.
>
> Assumption for dividing memory: Memory in the free lists is sparse upon starting
> compaction (which means that only few nodes are available), except for memory
> reducer GCs, which happen in idle time though (so it's less of a problem).
>
> BUG=chromium:524425
> LOG=N
>
> Committed: https://crrev.com/a805be73f6f97645450124f75c0f7417ec7b3e70
> Cr-Commit-Position: refs/heads/master@{#31329}

TBR=hpayer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:524425

Review URL: https://codereview.chromium.org/1412643002

Cr-Commit-Position: refs/heads/master@{#31332}