The cause for missing functions is that some of them are created
from compiled code (see FastNewClosureStub), and thus not get
registered in profiler's code map.

My solution is to hook on GC visitor to provide JS functions
addresses to profiler, only if it is enabled.

BUG=858
TEST=

Review URL: http://codereview.chromium.org/3417019

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5523 ce2b1a6d-e550-0410-aec6-3dcde31c8c00