Check whether the receiver to a keyed-call is actually a heapobject.

BUG=325225
LOG=n
R=dslomov@chromium.org

Review URL: https://chromiumcodereview.appspot.com/101863004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18241 ce2b1a6d-e550-0410-aec6-3dcde31c8c00