[heap] remove alignment requirement from AllocationInfo::limit

[heap] remove alignment requirement from AllocationInfo::limit

While all allocated objects need to have correct alignment, this requirement
doesn't make a lot of sense for the allocation limit. Removing this assertion
would makes it possible to make the inline-allocation-observers accurate. This
could be done in other ways, but removing this assertion is the most elegant way
to go about it.

R=hpayer@chromium.org
BUG=

Committed: https://crrev.com/a0253e8594176ecb086937be97101c07340dbdcb
Cr-Commit-Position: refs/heads/master@{#32013}

[Hannes Payer (out of office), 2015-11-16 11:31:47]

lgtm

[ofrobots, 2015-11-16 16:04:55]

The CQ bit was checked by ofrobots@google.com

[commit-bot: I haz the power, 2015-11-16 16:05:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1444883003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1444883003/1

[commit-bot: I haz the power, 2015-11-16 16:47:33]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-16 16:47:45]

Patchset 1 (id:??) landed as
https://crrev.com/a0253e8594176ecb086937be97101c07340dbdcb
Cr-Commit-Position: refs/heads/master@{#32013}