Reland of "[heap] Divide available memory upon compaction tasks"

Reland of "[heap] Divide available memory upon compaction tasks"

This reverts commit ec1046f9f8cd52488917b439c598296620103d39.

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}

[Michael Lippautz, 2015-10-16 08:30:19]

The CQ bit was checked by mlippautz@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-10-16 08:30:25]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1399403002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1399403002/20001

[commit-bot: I haz the power, 2015-10-16 09:04:39]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-10-16 09:04:40]

Dry run: This issue passed the CQ dry run.

[Michael Lippautz, 2015-10-16 09:18:56]

mlippautz@chromium.org changed reviewers:
+ hpayer@chromium.org

[Michael Lippautz, 2015-10-16 09:18:57]

PTAL - bug was present in ToT (since merging experimental GC ;)) and fixed
separately.

[Hannes Payer (out of office), 2015-10-16 10:23:32]

LGTM (rubber-stamped)

[Michael Lippautz, 2015-10-16 10:32:46]

The CQ bit was checked by mlippautz@chromium.org

[commit-bot: I haz the power, 2015-10-16 10:32:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1399403002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1399403002/20001

[commit-bot: I haz the power, 2015-10-16 10:34:08]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-16 10:34:34]

Patchset 2 (id:??) landed as
https://crrev.com/a805be73f6f97645450124f75c0f7417ec7b3e70
Cr-Commit-Position: refs/heads/master@{#31329}

[Michael Lippautz, 2015-10-16 11:54:13]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/1412643002/ by mlippautz@chromium.org.

The reason for reverting is: Failing:
https://chromegw.corp.google.com/i/client.v8/builders/V8%20Linux64%20GC%20Str....