CallSite.getFunctionName() is able to retrieve names for functions better than
getFunction().name.  Use it in CallSite.toString().

Code by marja@chromium.org.

BUG=NONE
TEST=stack-traces.js: Added testClassNames.

Review URL: https://chromiumcodereview.appspot.com/10384196

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11652 ce2b1a6d-e550-0410-aec6-3dcde31c8c00