port r23405.

original commit message:
  Added vector-based loadic hydrogen stubs. Not yet callable.
  The next step is to integrate the use of vector[slot] into the IC
  infrastructure so it can do the right thing for a vector-based ic.
   Then these stubs can be installed. For now, they immediately bail
   out to the miss handler.

BUG=
R=weiliang.lin@intel.com

Review URL: https://codereview.chromium.org/507993002

Patch from Chunyang Dai <chunyang.dai@intel.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23433 ce2b1a6d-e550-0410-aec6-3dcde31c8c00