Revision 9585:
Fix free list node ending up on evacuation candidate.

This is a temporary fix which avoids compaction when incremental marking
is restarted during an old-space-step. That could turn the page that
holds the chosen free list node into an evacuation candidate. It could
also cause several other inconsistencies if it happens during scavenge.

Revision 9580:
Adjust assertions in the incremental marking.

Now we are completely transfering marks when shifting arrays in-place.

This might lead to white free space objects in the marking deque.
Review URL: http://codereview.chromium.org/8194012

git-svn-id: http://v8.googlecode.com/svn/trunk@9586 ce2b1a6d-e550-0410-aec6-3dcde31c8c00