Fix Heap::AllocateFillerObject() to use double alignment param.

Fix Heap::AllocateFillerObject() to use double alignment param.

This is called from Runtime, and was dropping the requested alignment
for doubles. Needed for upcoming MIPS CL to remove some more
workarounds for load/store doubles.

BUG=

Committed: https://crrev.com/cbfb7cc1b16fa04f4d72fcc9119066b6d3c92e2c
Cr-Commit-Position: refs/heads/master@{#28413}

[paul.l..., 2015-05-15 06:26:44]

paul.lind@imgtec.com changed reviewers:
+ balazs.kilvady@imgtec.com, danno@chromium.org, dusan.milosavljevic@imgtec.com,
hpayer@chromium.org, jochen@chromium.org

[paul.l..., 2015-05-15 06:26:45]

PTAL.

[Hannes Payer (out of office), 2015-05-15 06:30:35]

lgtm

[paul.l..., 2015-05-15 06:31:28]

The CQ bit was checked by paul.lind@imgtec.com

[commit-bot: I haz the power, 2015-05-15 06:31:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1131123003/1

[commit-bot: I haz the power, 2015-05-15 06:49:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-15 06:50:02]

Patchset 1 (id:??) landed as
https://crrev.com/cbfb7cc1b16fa04f4d72fcc9119066b6d3c92e2c
Cr-Commit-Position: refs/heads/master@{#28413}