Allocate filler objects in the factory.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/240393003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20845 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Heap::AllocateStringFromOneByte() and major part of its callers handlified.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/239243018

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20846 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/bleeding_edge' into bleeding_edge