This allows to specify a constructor against which an implicit instance
check is performed for API accessors. If the receiver is incompatible,
an implicit TypeError is thrown and no callback is invoked.

R=svenpanne@chromium.org
BUG=v8:2075
TEST=cctest/test-api/InstanceCheckOn[*]

Review URL: https://chromiumcodereview.appspot.com/10442129

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11734 ce2b1a6d-e550-0410-aec6-3dcde31c8c00