Fix test-heap/LargeObjectSlotRecording.

Fix test-heap/LargeObjectSlotRecording.

Remove hard-coded assumption of large object size threshold.

This test fails on PPC in version 4.7 where the threshold is derived
directly from the allocator's pagesize.

R=hpayer@chromium.org, mstarzinger@chromium.org, michael_dawson@ca.ibm.com
BUG=

Committed: https://crrev.com/59a0641820c8599ec6a6650d7dea1e1424586628
Cr-Commit-Position: refs/heads/master@{#31963}

[MTBrandyberry, 2015-11-11 20:22:07]

The CQ bit was checked by mbrandy@us.ibm.com

[commit-bot: I haz the power, 2015-11-11 20:22:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1440723002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1440723002/1

[commit-bot: I haz the power, 2015-11-11 20:22:12]

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

[commit-bot: I haz the power, 2015-11-11 20:22:13]

No L-G-T-M from a valid reviewer yet. Only full committers are accepted.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[MTBrandyberry, 2015-11-11 20:26:08]

The CQ bit was checked by mbrandy@us.ibm.com to run a CQ dry run

[commit-bot: I haz the power, 2015-11-11 20:26:21]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1440723002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1440723002/1

[commit-bot: I haz the power, 2015-11-11 21:04:21]

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

[commit-bot: I haz the power, 2015-11-11 21:04:22]

Dry run: This issue passed the CQ dry run.

[Michael Starzinger, 2015-11-12 09:13:41]

LGTM.

[MTBrandyberry, 2015-11-12 14:31:20]

The CQ bit was checked by mbrandy@us.ibm.com

[commit-bot: I haz the power, 2015-11-12 14:31:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1440723002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1440723002/1

[commit-bot: I haz the power, 2015-11-12 14:33:05]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-14 23:20:47]

Patchset 1 (id:??) landed as
https://crrev.com/59a0641820c8599ec6a6650d7dea1e1424586628
Cr-Commit-Position: refs/heads/master@{#31963}