Revert of Reland "[heap] Turn on parallel compaction"

Revert of Reland "[heap] Turn on parallel compaction" (patchset #1 id:20001 of https://codereview.chromium.org/1460663002/ )

Reason for revert:
Failing:
  https://chromegw.corp.google.com/i/client.v8/builders/V8%20Linux64%20ASAN/builds/7903/

Original issue's description:
> Reland "[heap] Turn on parallel compaction"
>
> This reverts commit aa4688c1852d87223d208b9341e0ebb5127b6cd3.
>
> BUG=chromium:524425
> LOG=N
> CQ_EXTRA_TRYBOTS=tryserver.v8:v8_linux_arm64_gc_stress_dbg;tryserver.v8:v8_linux_gc_stress_dbg;tryserver.v8:v8_mac_gc_stress_dbg;tryserver.v8:v8_linux64_msan_rel;tryserver.v8:v8_linux64_tsan_rel
>
> Committed: https://crrev.com/ac1d2b21bbb50572b99de4bed568437d51468e01
> Cr-Commit-Position: refs/heads/master@{#32088}

TBR=hpayer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:524425
Committed: https://crrev.com/463a6d273da585e33cf452fead4e58a55826be04
Cr-Commit-Position: refs/heads/master@{#32089}

[Michael Lippautz, 2015-11-18 15:41:53]

Created Revert of Reland "[heap] Turn on parallel compaction"

[commit-bot: I haz the power, 2015-11-18 15:42:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1462523002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1462523002/1

[commit-bot: I haz the power, 2015-11-18 15:42:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-18 15:42:48]

Patchset 1 (id:??) landed as
https://crrev.com/463a6d273da585e33cf452fead4e58a55826be04
Cr-Commit-Position: refs/heads/master@{#32089}