from the constructor function. This works well for binding objects,
and this matches DevTools' algorithm for name assignment.

R=sgjesse@chromium.org
BUG=none
TEST=test-heap-profiler/GetConstructorName

Review URL: http://codereview.chromium.org/7709026

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9000 ce2b1a6d-e550-0410-aec6-3dcde31c8c00