source code positions it gets from the program counter to recreate the scope
chain by reparsing the function or program.

This CL includes the following changes
* Adds source code positions for the assignment added by the rewriter.
* Run the preparser over global code first.
* Use the ScopeType from the ScopeInfo to determine if the code being debugged
  is eval, function or global code instead of looking up the '.result' symbol.

TEST=mjsunit/debug-stepout-scope.js

Review URL: http://codereview.chromium.org/8590027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10076 ce2b1a6d-e550-0410-aec6-3dcde31c8c00