Deprecate HAllocateObject in favor of HAllocate.

This models the instantiation of an implicit receiver for CallNew nodes
in hydrogen using HAllocate together with generic stores instead of one
specialized HAllocateObject instruction, hence creating a single choking
point for inlined allocation in optimized code.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/15714005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14930 ce2b1a6d-e550-0410-aec6-3dcde31c8c00