Revert of Re-enable memory.top_7_stress test now that bug 455349 is fixed.

Revert of Re-enable memory.top_7_stress test now that bug 455349 is fixed. (patchset #1 id:1 of https://codereview.chromium.org/940283007/)

Reason for revert:
This is still failing on the bots, with a facebook login failure: http://build.chromium.org/p/chromium.perf/builders/Linux%20Perf%20%283%29/builds/9314/steps/memory.top_7_stress.reference/logs/stdio

Original issue's description:
> Re-enable memory.top_7_stress test now that bug 455349 is fixed.
>
> BUG=459646
>
> Committed: https://crrev.com/92fb7ce426ebe966630fbd0de62e59cee91a6e74
> Cr-Commit-Position: refs/heads/master@{#317606}

TBR=petrcermak@chromium.org,primiano@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=459646
Committed: https://crrev.com/68c37ac88179a49336ac619d863ebe93c0ece57f
Cr-Commit-Position: refs/heads/master@{#317668}

[sullivan, 2015-02-23 22:28:22]

Created Revert of Re-enable memory.top_7_stress test now that bug 455349 is
fixed.

[commit-bot: I haz the power, 2015-02-23 22:39:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/942113005/1

[commit-bot: I haz the power, 2015-02-23 22:41:35]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-23 22:43:38]

Patchset 1 (id:??) landed as
https://crrev.com/68c37ac88179a49336ac619d863ebe93c0ece57f
Cr-Commit-Position: refs/heads/master@{#317668}