X87: CallIC customization stubs must accept that a vector slot is cleared.

port r22668.

original commit message:
  CallIC customization stubs must accept that a vector slot is cleared.

  The CallIC Array custom IC stub read from the type vector, expecting
  to get an AllocationSite. But there are paths in the system where a type
  vector can be re-created with default values, even though we currently
  grant an exception to clearing of vector slots with AllocationSites in
  them at gc time.

BUG=
R=weiliang.lin@intel.com

Review URL: https://codereview.chromium.org/426203002

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

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22693 ce2b1a6d-e550-0410-aec6-3dcde31c8c00