Fix an issue with debugger 'step in' when calling function has local variables.Corresponding Chromium bug:http://code.google.com/p/chromium/issues/detail?id=15824
Review URL: http://codereview.chromium.org/149326

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2426 ce2b1a6d-e550-0410-aec6-3dcde31c8c00