Folded allocations marked for double alignment is not aligned if old dominator
size is used for offset to inner object.

TEST=mjsunit/big-array-literal on MIPS
BUG=
R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/103963005

Patch from Dusan Milosavljevic <Dusan.Milosavljevic@rt-rk.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18332 ce2b1a6d-e550-0410-aec6-3dcde31c8c00